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XACT-11C Scientific Calculator The Hewlett-Packard Compatible Scientific Calculator For Your IBM PC or Compatible CalcTech Incorporated 6014 NE 60th Street P.O. Box 15277 Seattle, WA. 98115-0277 Phone: 206-527-9950 Fax: 206-525-1331 Description XACT-11C is the Scientific Calculator of the XACT CALCULATORS series. XACT CALCULATORS emulate the functions of Hewlett- Packard's handheld HP-11C Scientific, HP-12C Financial, and HP-16C Programmer's calculators and include additional features such as program store to disk, simulated tape display, and constant memory. XACT CALCULATORS includes an auxiliary shell program. XSHELL.EXE is a Terminate-Stay-Resident (TSR) program which loads and runs all three calculators. (Note: A TSR is a program which remains loaded but inactive after it finishes execution. TSRs are usually made active by pressing a "hot-key" which pops up the program, even if another program is executing at the time). XSHELL.EXE has 3 hot-keys, one for each calculator. Normally, the disadvantage of TSRs is that they consume a lot of your computer's memory, even while they're inactive. Thus if you have loaded one or more TSRs, there may not be enough RAM left over to run your spreadsheet, word processor, or other DOS programs. XSHELL.EXE helps reduce "RAM Cram" because it REQUIRES ONLY 6K BYTES OF RAM! In fact, If you have EMS memory installed (see section 2.2) in your computer, XSHELL requires an amazingly small 1.5K bytes of conventional DOS memory!. Each calculator can be run individually as an ordinary DOS program by running either X11.EXE, X12.EXE, or X16.EXE. Or, all three calculators can be run as a single TSR by running XSHELL.EXE. XSHELL.EXE will deactivate and unload itself from RAM after 8 minutes until you register your copy. This will allow you to try XACT CALCULATORS as a TSR before you register. Once XSHELL.EXE unloads itself, your computer will behave as though XSHELL had never been loaded in the first place. To re-activate XSHELL, simply run the program again. It will again remain loaded for another 8 minutes. - 2 - Quick Registration for XACT CALCULATORS Registration for XACT CALCULATORS is only $27.00. To register, print a copy of the file ORDERFRM.DOC and fax or mail the completed form to us. We will quickly fax (or mail) back your registration serial number and personal unlock code. Run the QUICKREG.EXE program entering your name, serial number, and unlock code and that's it, you're registered! QUICKREG.EXE serializes XSHELL.EXE and "unlocks" it's 8 minute time limit. AFTER YOU'VE REGISTERED AND SUCCESSFULLY RUN QUICKREG.EXE, XSHELL.EXE WILL NO LONGER HAVE AN 8 MINUTE TIME LIMIT. It will remain resident in your computer's RAM (waiting for a hot-key to become active) until you reboot or manually unload XSHELL. If you prefer to order your registered copy by mail, feel free to mail in your completed form. A copy of the file ORDERFRM.DOC is shown on the following page. - 3 - ---------------------------------------------------------------------- FAX this form to: (206)-525-1331 or mail to: CalcTech, Inc. 6014 NE 60th Street P.O. Box 15277 Seattle, WA. 98115-0277 ---------------------------------------------------------------------- XACT CALCULATORS - Version 5.1 QUICK REGISTRATION FORM I wish to register my copy of XACT CALCULATORS (includes XACT-11C Scientific, XACT-12C Financial, and XACT-16C Programmer) today for $27.00 (Washington state residents add 8.2% sales tax). Please (check one or more boxes below): [ ] FAX my serial number and personal unlock code as soon as possible. My FAX number is: ____________________________ [ ] Mail my serial number and personal unlock code as soon as possible. [ ] Send my registered copy by mail. (Enclose an an additional $5.00 for U.S. or Canada, $10.00 for overseas air mail). I prefer (check one): [ ] 5.25" or [ ] 3.5" diskettes Name: ______________________________ Company:_________________________ Phone: (Day) ______________________ (Evening) ________________________ Address: _____________________________________________________________ City: ______________________________ State: ________ Zip: ____________ Comments: ____________________________________________________________ ______________________________________________________________________ (check one): [ ] VISA [ ] Mastercard [ ] Check Enclosed Credit card #: ____________________________________ Expires: ____/____ Cardholder's Name (Please print): ____________________________________ Cardholder's Signature: ______________________________________________ - 4 - Background Information CalcTech, Inc. is a company with a respected history in the development of software calculators. The article "TSR Desktop Organizers", (PC Magazine, Aug. 1987), contained a review of the leading desk accessory programs. Three of the fourteen products reviewed incorporated calculators developed by CalcTech. A CalcTech calculator has also won PC Magazine's prestigious "Editor's Choice" award. CalcTech has developed calculators for publishers and OEM's such as Software Publishing Corp., Bellsoft Inc., DAC Software, Popular Programs Inc., Timeworks Inc., Practical Peripherals, and Monogram Software. Here's What A Few Industry Experts Have To Say: "XACT-16C... It has power to burn." --Johnathan Matzkin, PC Magazine. "PC-12C's (OEM version of XACT-12C) emulation of the HP-12C is exact, it gets my vote." --Jim Seymour, PC Magazine "I found Bellsoft's (OEM version) Pop-Up calculator to be the best for office work" --Mark J. Welch, BYTE. "When a program performs flawlessly, it makes writing a review hard. Such is the case with XACT CALCULATORS." --Jacques Benavente, PCM Magazine XACT CALCULATORS have won PC Brand's 1989 award for outstanding technical merit in a shareware program. An Important Note About The Shareware Concept XACT CALCULATORS are copyrighted shareware programs. They are not freeware or public domain software. Payment is made through registration and is on the "honor system". We ask that you pay for the programs by registration if after a reasonable trial period, you find them to be useful in your work. We hope that you appreciate the "try before you buy" concept that shareware products like XACT CALCULATORS provide and that you will take the time to register. Anyone who has ever purchased expensive (or even inexpensive) software can attest to the frustration of being "burned" by a lousy product. We think XACT CALCULATORS are excellent products and we're giving you the opportunity to judge for yourself. If you agree, please take a moment to register. - 5 - Customer Support Support for XACT CALCULATORS is provided to registered users using our voice messaging "access code" feature. You can call us at (206)-527-9950 and leave your question on our voice messaging system. You will be given an "access code" which is a password for your message. You may then call back (usually within 1 day), enter your access code using your touch-tone phone, and receive a voice message response to your question. Alternatively, registered users can send your question via E-mail on CompuServe at 71641,1721 or by U.S. mail. When contacting customer support, please be as specific as possible with your question and be sure to mention the version number of your copy of XACT CALCULATORS. User Groups, Electronic Bulletin Boards, Disk Vendors User Groups, BBS SysOps, and Disk Vendors may receive an official copy of the latest shareware version of XACT CALCULATORS by submitting a written request to CalcTech, Inc. Please add CalcTech to your organization's mailing list and send any appropriate information such as your group's newsletter or catalog. Private Labels, Custom Versions Private labellings and/or custom versions of XACT CALCULATORS can be developed for your organization. Please contact CalcTech, Inc. by in writing for a quotation. Government, Corporate, Academic Site Licensing A site license grants you the legal right to make multiple copies of a "master" registered version and it's documentation for your organization or group. A site license is non-transferable. We accept Visa and Mastercard, personal or corporate checks, and written (fax ok) purchase orders (NET 30, FOB Seattle, WA.) for site license registration. The following page is a site license form you can use to fax or mail or mail to us for site licensing. - 6 - ---------------------------------------------------------------------- FAX this form to: (206)-525-1331 or mail to: CalcTech, Inc. 6014 NE 60th Street P.O.Box 15277 Seattle, WA. 98115-0277 ---------------------------------------------------------------------- XACT CALCULATORS - Version 5.1 Site License Registration Form Use this form to obtain a site license for your company or group. Your registered copy will be sent via U.S. mail. I wish to register XACT CALCULATORS under a multiple (site) license agreement. Please license my organization to allow us to duplicate up to: (check one) [ ] 10 copies .................................... $100.00 [ ] 100 copies ................................... $350.00 [ ] 1000 copies ................................. $1000.00 WA. state residents add 8.2% ................ $_______ TOTAL $_______ Company or Group Name: _______________________________________________ Your Name: ___________________________________ Phone: ________________ Address: _____________________________________________________________ City: ______________________________ State: _________ Zip: ___________ Method of Payment: (check one) [ ] Check enclosed [ ] Bill Me. Terms are NET 30, FOB Seattle, Washington Our Federal taxpayer I.D. number is: 91-1382828 Purchase Order Number (optional): ___________________________ [ ] Charge my Visa or Mastercard Cardholder's Name: __________________________________________ Credit Card #: ____________________________ Expires:____/____ - 7 - License Agreement You are hereby granted permission to use this software and to distribute copies of the software and documentation in its original form as long as it is not distributed for profit (handling fees less than $5.00 are ok). ONLY COPIES OF THE SHAREWARE VERSION OF THIS SOFTWARE AND DOCUMENTATION MAY BE DISTRIBUTED IN ANY FORM. You are not allowed to make copies (except for backup purposes only) or distribute this software and documentation once the software has been registered. THE SOFTWARE HEREIN ARE PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAMS IS WITH YOU. IN NO EVENT SHALL CALCTECH OR ANY OF IT'S OFFICERS, DIRECTORS, SHAREHOLDERS, EMPLOYEES, AFFILIATES, OWNERS, OR OTHER RELATED PARTIES BE LIABLE TO YOU OR ANY OTHER THIRD PARTY FOR DAMAGES INCLUDING ANY LOST PROFITS, LOST SAVINGS, OR OTHER INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OF OR THE INABILITY TO USE THIS PRODUCT OR AS TO THE PERFORMANCE OF THIS PRODUCT EVEN IF WE HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES IN ADVANCE. SOME STATES DO NOT ALLOW THE LIMITATION OR EXCLUSION OF LIABILITY FOR INCIDENTAL OR CONSEQUENTIAL DAMAGES SO THE ABOVE LIMITATION OR EXCLUSION MAY NOT APPLY TO YOU. THIS AGREEMENT IS GOVERNED BY THE LAWS OF THE STATE OF WASHINGTON. Trademarks/Copyrights HP-11C, HP-12C, and HP-16C are trademarks of Hewlett-Packard Co. Lotus is a trademark of Lotus Development Corp. Intel is a trademark of the Intel Corp. PC-DOS, IBM-PC, PC-XT, PC-AT and PS/2 are trademarks of IBM. MS-DOS, Microsoft Windows and Microsoft Word are trademarks of Microsoft Corp. Copyright (C) 1987-1990, 1991 by CalcTech Inc. All rights reserved. Specifications herein are subject to change without notice. - 8 - TABLE OF CONTENTS Section Title Page 1 Getting Started .......................................... 11 1.1 Introduction ......................................... 11 1.2 Other Guides ......................................... 11 1.3 System Requirements .................................. 11 1.4 Installing XACT-11C and Making Backups ............... 12 1.5 Command Line Options & Changing Hot Keys ............. 12 1.6 Using XACT-11C with Microsoft Windows ................ 13 1.7 Using XACT-11C on a Network .......................... 13 2 Running XACT-11C .......................................... 14 2.1 Running XACT-11C as a stand-alone DOS program......... 14 2.2 Running XACT-11C as a TSR Program .................... 14 2.3 XACT-11C as a Removable TSR Program .................. 15 2.4 Keyboard Conventions ................................. 16 2.5 Function Keys ........................................ 16 2.6 Prefix Keys .......................................... 16 2.7 Entering Numbers ..................................... 17 2.8 Short Cut Keys ....................................... 17 3 Basic Operations .......................................... 17 3.1 Setting the Display Format ........................... 17 3.2 Arithmetic Calculations and RPN ...................... 17 3.3 Clearing Numbers ..................................... 18 3.4 Negative Numbers ..................................... 18 3.5 Mathematical Operations .............................. 19 3.6 Percentage Operations ................................ 20 3.7 Exponential Notation ................................. 20 3.8 Memory Storage Registers ............................. 21 3.9 Stack Operations ..................................... 21 3.10 The LastX Register ................................... 21 3.11 The Index Register and Using Memories Indirectly ..... 22 4 Scientific Functions ...................................... 22 4.1 Trigonometric Functions .............................. 22 4.2 Angle Conversions .................................... 23 4.3 Polar/Rectangular Conversions ........................ 23 4.4 Permutations and Combinations ........................ 24 4.5 Random Numbers ....................................... 24 - 9 - Section Title Page 5 Features .................................................. 24 5.1 Getting Help ......................................... 24 5.2 Viewing the Tape ..................................... 25 5.3 Stamping the Tape .................................... 25 5.4 Printing the Tape .................................... 25 5.5 Storing the Tape ..................................... 25 5.6 Loading a Program .................................... 25 5.7 Storing a Program .................................... 26 6 Programming ............................................... 26 6.1 Entering a Program into XACT-11C ..................... 26 6.2 Labels in Programs ................................... 27 6.3 Using Subroutines .................................... 28 6.4 Returning from a Program or Subroutine ............... 28 6.5 Entering Data and the Run/Stop Key ................... 28 6.6 The [GoTo] Instruction ............................... 29 6.7 Branching Using the Index Register ................... 29 6.8 Program Loops Using the Index Register ............... 30 6.9 Program Loops and Branches Using the X and Y Registers 31 6.10 Branching on Flags Set/Clear ......................... 31 6.11 The Single Step Instruction .......................... 32 6.12 Moving to a Program Line Number ...................... 32 6.13 Inserting and Deleting Program Lines ................. 32 7 Statistical Calculations .................................. 33 7.1 Entering and Removing Numbers ........................ 33 7.2 Statistical Mean ..................................... 33 7.3 Standard Deviation ................................... 34 7.4 Linear Estimate ...................................... 34 7.5 Linear Regression .................................... 35 Appendix / Error Conditions ................................... 36 - 10 - 1. Getting Started 1.1 Introduction XACT CALCULATORS are software which emulate the functions of the handheld models of Hewlett-Packard's HP-11C Scientific, HP-12C Financial, and HP-16C Programmer's calculators. If you are familiar with one or more of these calculators, you will find that you already know how to use XACT CALCULATORS. If not, you'll find XACT CALCULATORS easy to learn and use. They will become an invaluable tool in your work. XACT-11C is the Scientific Calculator program. XACT CALCULATORS also incorporate the XACT-12C Financial Calculator and the XACT-16C Programmer's calculator. If you are already familiar with DOS and with the HP-11C, you may only need to read Chapters 2 and 3. This will provide enough information to get you started. If you are new to DOS and/or the HP-11C, you may wish to read, or at least skim, Chapters 1 through 6. 1.2 Other Guides There are a number of guides and references available for the HP-11C that can be used with XACT-11C as well. These are generally available in bookstores and other places where Hewlett- Packard calculators are sold. Some of these publications are listed below. "HP-11C Owner's Handbook and Problem Solving Guide" Covers general operations, functions, applications, and programming of the HP-11C. Published by the Hewlett-Packard Company. Grapevine Publishing, Inc. P.O. Box 118, Corvallis, OR, 97339, also has a number of publications about the HP-11C. 1.3 System Requirements To operate the XACT-11C calculator, you will need an IBM PC, PC- XT, PC-AT, PS/2, or close compatible equipped with at least the following: 256K RAM One floppy disk drive PC-DOS or MS-DOS version 3.00 or later - 11 - 1.4 Installing XACT CALCULATORS and Making Backups You should make a copy of the programs contained on the XACT CALCULATORS diskette for backup purposes. Use the DOS "copy" command to copy all the files to another diskette or to your hard disk. There may be a file named README.DOC on your disk. If so, you should examine it using your word processor or the DOS "type" command. 1.5 Command Line Options/Changing Hot-Keys A command line option is an additional command typed when you first load X11.EXE or XSHELL.EXE. There are several of these options available. For example, if you wish to start XACT-11C in scientific notation, you would type: x11 /sci [ENTER] ([ENTER] means press the ENTER key). The following is a list of available command line options when running XACT-11C. /mono Force XACT-11C into monochrome mode /sci Start up XACT-11C in scientific notation /nomouse Disable mouse operation /nosignon Disable the signon screen /swap=<path> Directory/Path used to store swap files There are additional command line options available when running the program XSHELL.EXE. The following is a list of these options. /alt Changes invocation key to Alt-s (XACT-11C), Alt-f (XACT-12C), Alt-p (XACT-16) /alt-ctrl Change invocation key to Alt-Ctrl-s (XACT-11C), Alt-Ctrl-f (XACT-12C), Alt-Ctrl-p (XACT-16C) /mono Force XACT CALCULATORS into monochrome mode /sci Set scientific notation (XACT-11C only) /noems Disable EMS memory usage (if EMS memory present) /nomouse Disable mouse operation /nosignon Disable the signon screen /swap=<path> Directory/Path used for swap files. (See section on using XACT CALCULATORS on a network) /wsize=nn Set word size (XACT-16C only). Valid settings for nn are 2 to 64. /radix=n Set radix (XACT-16C only). Valid settings for n are h,d,o,b, or f (hex,dec,oct,bin,float) - 12 - 1.6 Using XACT-11C with Microsoft Windows If you use Microsoft Windows, you may wish to set up Windows to run XACT-11C. XACT-11C will run as an ordinary "text mode" application under Windows which can be set up to be either windowed or in full screen mode. To run XACT-11C under Windows, you should first create a PIF file which is used to "describe" the program to Windows. Use the PIF editor (pifedit.exe) to create an x11.pif file. For the "optional parameters" field, type in /nosignon so that XACT-11C won't display it's startup screen every time you click on it's icon. Also make sure that the "KB required" field is set to 128. (For additional information on using the PIF editor, see your Windows documentation). Once you have created a PIF file, you will probably want to create an icon so you can easily invoke XACT-11C by double clicking on an icon. We have supplied a custom icon you can use to do this. From the Windows program manager, create a new program item and in the "command line" field, type in x11.pif. Then select the "change icon" button and type in xact.ico. (If you're unclear on these procedures, they're also covered in Microsoft's Windows documentation). 1.7 Using XACT-11C on a Network XACT-11C and all XACT CALCULATORS are compatible with most networks. If you wish to use them on a network, read the following information. All XACT CALCULATORS use a technique known as swapping in order to save memory as well as save the state of each calculator each time you finish using it. Swapping creates a number of "temporary" files. By default, these files are saved in the same directory as the XACT CALCULATOR programs themselves. If two or more users on a network are running a calculator, their swap files will eventually corrupt each other, causing unpredictable results. There are 2 different ways to avoid this problem. Both involve changing the directory in which the swap files are stored. The first method is by using an environmental variable to tell XACT CALCULATORS the path to use to store its swap files. For example, assume you have 2 network users (Jan and Bill) each of which have access to network drive N:. Assume also that the directorys N:\USER\JAN\TEMP and N:\USER\BILL\TEMP have already been created on drive N: The environmental variable can be set by putting the following statement in Jan's AUTOEXEC.BAT file: SET XACT=N:\USER\JAN\TEMP - 13 - whereas Bill's AUTOEXEC.BAT file would contain the statement: SET XACT=N:\USER\BILL\TEMP Now even though Jan and Bill may be running the same copy of one of the calculators, they would each have separate copies of swap files and there would be no conflict. The second method uses the same idea, however, the swap path is chosen from the command line. For example: X11 /SWAP=C:\TEMP would place the swap files in the directory C:\Temp, assuming it existed. 2. Running XACT-11C 2.1 Running XACT-11C as a stand-alone DOS program To run XACT-11C, at the DOS prompt type: x11 [ENTER] 2.2 Running XACT-11C as a TSR program To run XACT-11C as a TSR program, type xshell [ENTER] You will see the copyright message appear on the screen. The computer will then return to the DOS prompt and appear as if nothing had happened. However, the XACT CALCULATORS shell program has now been loaded into your computer's memory. To activate XACT-11C, press: Alt-Shift-S XACT-11C will now appear on your screen, ready to perform calculations. To exit from XACT-11C, press the Esc key. In a likewise fashion, to run the XACT-12C financial calculator, you would instead press Alt-Shift-F, and to run the XACT-16C Programmer's calculator you would press Alt-Shift-P. You can also unload XSHELL from RAM by pressing Alt-Shift-U. When you run XSHELL, it will use between 1.5K and 6K bytes of your computer's RAM. To determine exactly how much memory XSHELL is using, you can run the DOS command "chkdsk" both before and - 14 - after running XSHELL and noting the difference in memory bytes free. If you are unfamiliar with this command, see your DOS reference manual. EMS (Expanded memory specification) memory is a type of memory specification that was developed jointly by Lotus, Intel, and Microsoft. EMS memory was developed as a work-around to get around the 640K DOS memory limitation. In order to use EMS memory, a program must be written specifically to use EMS memory (if available). XSHELL is such a program. If you have an EMS memory board installed in your computer, XSHELL will put as much of itself in EMS memory as it can and will also "swap" your computer's memory to EMS memory when you pop-up a calculator. With EMS memory installed, XSHELL will require less than 1.5K of DOS memory!. If you don't have EMS memory but have a 386 computer, there are several commercial programs available which can "simulate" EMS memory. Even if you don't have EMS memory installed, XSHELL requires less than 6K bytes of DOS memory. Without EMS memory, XSHELL will swap to disk, creating the file XSHELL.SWP. This file may be as large as 131k bytes. If you have not registered your copy of XACT CALCULATORS, you will only be able to use them as a TSR program for 8 minutes before they automatically unload themselves from memory. After 8 minutes, you will hear a tone telling you that XSHELL is unloading. You will have to run XSHELL again in order to use XACT CALCULATORS as a TSR. Once you have registered and received your serial number and unlock code, you can enter these numbers into the program QUICKREG.EXE which will remove the 8 minute limit from XSHELL. You can always run X11.EXE as a (non-TSR) DOS program without any limitations whatsoever. 2.3 XACT-11C as a Removable TSR Program When the shell program is loaded as a TSR program as in section 2.1 above, it remains loaded in your computer's memory until your computer is rebooted or powered off. To unload the shell program, press: Alt-Shift-U Unloading the shell program will not work if any other TSR programs have been loaded after XSHELL.EXE. Unfortunately, this is a limitation of MS-DOS itself. - 15 - 2.4 Keyboard Conventions Throughout this manual, XACT-11C function keys are denoted within a box. For example, the function key for the sine function is shown as [SIN]. In the case of function keys which require a prefix key (discussed in the next section), the prefix key is not given in this manual since it can easily be determined. Keys on the PC keyboard are listed in this manual using single quotes such as 'a'. Numbers to be entered into XACT-11C are shown in normal type. 2.5 Function Keys XACT-11C has approximately 70 different function keys arranged in the same ordering as on the HP-11C. Function keys are arranged in groups of up to 3 functions per key; an upper, a lower and a middle function all correspond to one function key. The upper and lower functions are invoked by first pressing a prefix key (discussed in the next section) and then the function key. The middle function does not require the use of a prefix key. The PC keystroke corresponding to function key is shown immediately to the left of the function box. The first row of function keys use the PC keys F1 through F10. The second through fourth rows use the alphabetic characters as arranged left to right on your PC keyboard. For example, the [SIN] function on XACT-11C is invoked by pressing the letter 'e' on the PC keyboard. Likewise, the [RCL] function is invoked by pressing the letter 'b'. The [e^x] function is invoke by pressing F2. 2.6 Prefix Keys The left shift key and the right shift key on the PC keyboard operate as prefix keys. They are equivalent to the gold [ f ] key and the blue [ g ] key on the HP-11C. Prefix keys allow you to activate the upper and lower functions assigned to a PC function key. For example, to invoke the [HYP] function, you would press and release the left shift key, and then press the letter 'w'. Likewise, to invoke the [HYP-1] function, you would press and release the right shift key and then press the letter 'w'. To invoke the [LOG] function, press and release the right shift key, and then press F3. - 16 - 2.7 Entering Numbers To enter numbers into XACT-11C, use the numeric keypad on the right side of your keyboard or the numbers on the typewriter portion of the keyboard. 2.8 Short Cut Keys You can use the Enter key on the PC, (also known as the Return key) as the XACT-11C [ENTER] key as a short cut. Also, the '+', '-', '*', and '/' keys adjacent to the numeric keypad function as you would expect. 3. BASIC OPERATIONS 3.1 Setting the Display Format When you first start it up, XACT-11C defaults to displaying 4 digits to the right of the decimal point. To change this setting, you can use the [Fix], the [Sci] or the [Eng] function keys followed by a number from 0 to 9 (enter numbers using the numeric keypad). This number represents the number of digits displayed to the right of the decimal point. The [Fix] function is used to display numbers in fixed (non-exponential notation) format. A number will not be displayed in exponential notation unless it is too large to be displayed. The [Sci] function is used to display numbers in scientific notation. The [Eng] (Engineering) display function is much like the scientific format except that the exponent displayed will always be a multiple of 3 (kilo). Note that the display format does not affect the number of digits used to perform calculations, only the way in which they are displayed. If you were using a 2 digit display format, the number 12.006 would be shown on the display as 12.01. In this example, the display has been rounded to 2 digits past the decimal point. However, the internal representation of the number is still kept as 12.006, and this value would be used in subsequent calculations. To round the number internally to match the number in the display use the [Rnd] key. In the above example, if the [Rnd] key were pressed, the internal value 12.006 would be converted to 12.01. To set the display format for scientific notation, use the [Sci] function key, again followed by a number between 0 and 9. For engineering notation (the exponent is a multiple of 3), use the [Eng] function key followed by a number between 0 and 9. - 17 - 3.2 Arithmetic Calculations and RPN You may already be familiar with Reverse Polish Notation (RPN). RPN is a type of calculator logic that eliminates the need for the equals key and the use of parenthesis in computations. Instead, multiple operands are entered into the calculator separated by the [ENTER] key. For example, to add the numbers 3 and 4: Keystroke Display Comment ================================================================ 3 [ENTER] 3.00 4 [ + ] 7.00 Add 3 + 4 The result, 7.00 is now displayed. To multiply this result by 5: Keystroke Display Comment ================================================================ 5 [ * ] 35.00 7.00*5.00 The way that XACT-11C performs these calculations with RPN is by using a stack. The stack consists of 4 registers: X, Y, Z, and T. Any number displayed is said to be in the X register. When the [ENTER] key is pressed, a number in the X Register is pushed into the Y Register and the previous number in the Y Register is pushed into the Z Register. The previous number in the Z register is pushed into the T Register. T stands for "Top" and represents the top of the stack of numbers. The previous value of the T register is lost. When a function key such as the [+] key is pressed, the value held in the Y register is added to the X register and this result is now stored in the X register. Pressing [ENTER] does one other thing, it leaves the stack disabled. This means that a number entered after the [ENTER] key has been pressed is not pushed on the stack, it remains in the X register. When a calculator function key is pressed, it utilizes numbers on the stack to perform the function. Depending upon the function, it may alter the X and/or Y registers, and also leave the stack enabled or disabled. Most operations leave the stack "enabled" so that the next number entered will first push the stack. The [ENTER] and the [CLx] functions are the most notable exceptions to this rule. 3.3 Clearing Numbers You can clear a number in the display by pressing the [CLx] function key. The calculator is now ready to accept another entry. Unlike other calculators, XACT-11C does not require a key for clearing a number and a different key for clearing the last - 18 - entry. Whether you have made a mistake in adding a series of numbers, or simply wish to start a new calculation, use the [CLx] function key. The [Bksp] key will clear a number in two different manners. If you are in the process on entering a number, but have not pressed a function key yet, the [Bksp] key will clear the last numeric digit entered. On the other hand, if the most recent key pressed was a function key (for example, the [e^x] key), pressing [Bksp] works just like the [CLx] key, it clears the number in the x register. XACT-11C also contains other function keys to clear the following: [S] (Greek Sigma character) Clear Sum. Used to clear statistical registers. [Prgm] Clear Program. Used to clear the program memory when programming XACT-11C. [Reg] Clear Registers. Used to clear all registers; [Prfx] Clear the [ f ] or [ g ] prefix keys. 3.4 Negative Numbers To change the sign of a number in the display, press the [ChS] (Change Sign) function key. The [ChS] function will toggle the sign of the value in the display. The [ChS] key is also used to change the sign of an exponent if you are using exponential notation. 3.5 Mathematical Operations XACT-11C contains a large number of commonly used mathematical functions. [x^2] Square of a number. [ x ] Square root of a number. [Ln] Natural log of a number. [Log] Base 10 log of a number. [10^x] Raise 10 to the value in the x register [e^x] Exponential of a number. [1/X] Reciprocal of a number. [Intg] Return the integer portion of a number. [Frac] Return the fractional portion of a number. [y^x] Raise a number to a power of another number. - 19 - 3.6 Percentage Operations Use the [ % ] key to calculate the percent amount of a number and the [D%] (the D is shown as a Greek delta symbol on XACT-11C) to calculate the difference in percent one number is from another. Determine the total amount you would pay for a $39.95 radio if the sales tax is 8.1%. Keystroke Display Comment ================================================================ 39.95 [ENTER] 39.9500 8.1 [ % ] 3.2360 Sales tax [ + ] 43.1860 Total paid. You would pay $43.19 including sales tax. What is 20% of $3500.00? Keystroke Display Comment ================================================================ 3500 [ENTER] 3500.00 20 [ % ] 700.00 Example: Gasoline prices fell last month from an average of $1.09 to $.98. What percent difference does this represent? Keystroke Display Comment ================================================================ 1.09 [ENTER] 1.0900 .98 [D%] -10.0917 Gasoline prices have fallen 10.09%. 3.7 Exponential Notation Use exponential notation to enter very large or very small numbers into XACT-11C. The [EEx] function key is used to enter an exponent. For example, to enter the number 12 E09 (12,000,000,000) type: Keystroke Display Comment ================================================================ 12 [EEx] 9 12.0000 +09 Likewise, to enter the number 12-09, type: - 20 - Keystroke Display Comment ================================================================ [CLx] 0.0000 12 [EEx] 9 12.0000 +09 [ChS] 12.0000 -09 3.8 Memory Storage Registers XACT-11C contains 20 different memory storage registers, used to perform storage and memory arithmetic calculations. These memories will retain their values until your computer is powered off or re-booted. Memory registers in XACT-11C are referred to as R0-R9 (for register 0 through 9), and R.0 through R.9. For example, to store the value 20.3 in memory register 2, type: Keystroke Display Comment ================================================================ 20.3 [Sto] 2 20.3000 To add the number 9.6 to the contents of register 2, type: Keystroke Display Comment ================================================================ 9.6 [Sto] [ + ] 2 9.6000 Now, if you wish to view the contents of memory register 2, type: Keystroke Display Comment ================================================================ [Rcl] 2 29.9000 Memory register 2 contains the value 29.90. 3.9 Stack Operations The [x<>y] function exchanges the contents of the X and Y registers. The [R|] (shown as R followed by an arrow pointing downward on XACT-11C) function rolls down the stack. The T register is copied into the Z register. The Z register is copied into the Y register, and the Y register is copied into the X register. The X register is "rolled around" into the T register. 3.10 The LastX Register The [LSTx] function key is not technically a part of the stack. It is used to recover numbers entered just before a mathematical operation was performed on the stack. The number recovered is held in a register referred to as the LastX register. For example, assume you meant to add the numbers 12 and 5 but accidentally pressed 6 instead of 5. - 21 - Keystroke Display Comment ================================================================ 12 [ENTER] 12.00 6 [ + ] 18.00 Wrong value [Lstx] 6.00 [ - ] 12.00 Subtract 5 [ + ] 17.00 Correct result 3.11 The Index Register and Using Memories Indirectly Memories can also be accessed indirectly using the Index register. The index register is accessed with the [I] function key. A number may be stored in the index register using [Sto] [I] and recalled from the index register using [Rcl] [I]. Also, the [x<>I] function key is used to exchange the X register with the Index register in the same fashion as the [x<>y] function key is used to exchange the X and Y registers. For example: Keystroke Display Comment ================================================================ 5 [Sto] [ I ] 5.0000 Register I= 5 20 [Sto] [(i)] 20.0000 Register 5 = 20 [CLx] 0.0000 Clear X reg [Rcl] 5 20.0000 Reg 5 = 20 In the above example, the Indirect Index Register [(i)] was used to store a number indirectly. The memory register accessed was determined by the contents of the [I] register. Memories can also be recalled indirectly using the operation [Rcl] [(i)], and exchanged with the X register indirectly using the [x(i)] function. 4. SCIENTIFIC FUNCTIONS XACT-11C provides a rich set of scientific and trigonometric functions to choose from. Each of these will be described below. 4.1 Trigonometric Functions XACT-11C contains a complete set of trigonometric functions, including hyperbolics. Trig functions can be displayed in either Degrees by pressing the [Deg] function key; Radians by pressing the [Rad] function key, or Grads by pressing the [Grd] function key. The available trig functions are as follows: [Sin] Sine function [Cos] Cosine function [Tan] Tangent function - 22 - [Sin-1] Arc Sine function [Cos-1] Arc Cosine function [Tan-1] Arc Tangent function In addition, the [Hyp] or the [Hyp-1] functions can be pressed prior to pressing [Sin], [Cos], or [Tan] functions to compute the hyperbolic or inverse hyperbolics of these functions. Keystroke Display Comment ================================================================ [Deg] Degree mode 30 [Sin] 0.5000 Sine of 30 degrees [Rad] 0.5000 Use radian mode. [Pi] 3.1416 [Cos] -1.0000 Cosine of Pi radians [Deg] -1.0000 Use degree mode. 1 [Tan-1] 45.0000 Arc Tangent of 1 4.2 Angle Conversions Use XACT-11C to convert from Degrees to Radians and from Radians to Degrees with the [->Rad] and [->Deg] functions respectively. You can also convert from fractional degrees (or fractional hours) to minutes and seconds with the [->H.ms] key and from minutes and seconds to fractional degrees with the [->H] function key Keystroke Display Comment ================================================================ 60 [Rad] 1.0472 Convert to radians 1.333 [H.ms] 1.1959 1 hr 19 min 59 sec 4.3 Polar/Rectangular Conversions XACT-11C can convert between polar and rectangular coordinates with the [->P] and [->R] functions respectively. For polar coordinates, the magnitude "r" is placed/returned in the y register, and the angle theta is placed in the x register. Theta may be in degrees, radians, or grads depending upon the trig mode set. For rectangular coordinates, the y coordinate is placed in the y register and the x coordinate in the x register. Keystroke Display Comment ================================================================ 1 [ENTER] 1.3 1.3000 x = 1.3, y = 1.0 [->P] 1.6401 magnitude "r" = 1.6401 [x<>y] 37.5686 theta = 37.5686 degrees - 23 - 4.4 Permutations and Combinations XACT-11C can calculate the two most common probability functions. Combinations are the number groups of y items, taken in groups of x, without regard to their order. Permutations are the number of different changes in position possible within a group of y where the group size is x. For example, the number of different permutations and combinations of the group 1 through 7 inclusive, taken 3 at a time are: Keystroke Display Comment ================================================================ 7 [ENTER] 7.0000 3 [Cy,x] 35.0000 combinations 7 [ENTER] 7.0000 3 [Py,x] 210.0000 permutations 4.5 Random Numbers XACT-11C will generate a different random number each time the [Ran#] function key is pressed. The generated number will be in the range 0 < n < 1. In addition, a random number "seed" may be planted by storing an arbitrary number between 0 and 1 in the Random number generator register. Keystroke Display Comment ================================================================ [Ran#] 0.4100 Random number [Ran#] 0.1847 Random number .123 [Sto] [Ran#] 0.1230 An arbitrary seed. [Ran#] 0.6334 Random number with seed 5. Features 5.1 Getting Help A Help menu is available when you are working with XACT-11C. To obtain help press: Alt-F1 An information screen will appear in a window. The help menu can be removed by pressing F1 again. - 24 - 5.2 Viewing the Tape XACT-11C provides a simulated tape display which keeps a record of your calculations as you perform them. To view the tape press: Alt-F2 The tape will appear in a window. To remove the tape, press F2 again. 5.3 Stamping the Tape To stamp a message on the simulated tape press: Alt-F4 The message will appear on the tape as well as the printer or tape disk file if either of these options are being used. 5.4 Printing the Tape To print the tape as you make calculations press: Alt-F5 To turn off printing, press F5 again. 5.5 Storing the Tape The simulated tape may be saved to a disk file as you make calculations. Each time you use XACT-11C, calculations are appended to the tape file. To store the tape, press Alt-F6 The tape will be saved under the name X11.ASC in the directory which you started XACT-11C in. 5.6 Loading a Program To load a program previously saved press: Alt-F7 - 25 - A window will appear requesting a file name. Enter the DOS filename of the program you wish to retrieve. 5.7 Storing a Program XACT-11C allows you to save programs as disk files. To save a program on disk, press: Alt-F8 A window will appear prompting you for comments. You can enter up to 3 lines of comments, associated with the program you are saving. Press the Esc key after you have entered any comments. Another window will appear prompting you for a filename. Enter any valid DOS filename. 6. PROGRAMMING Programming XACT-11C is a process whereby you "teach" the calculator a series of keystrokes, similar to the way you would normally enter the keystrokes if you were computing a problem manually. In addition, you can have a program take different actions in a program based upon values contained in registers. For example, the program could take a different course of action if the value contained in the X register is less-than-or-equal-to the value in the Y register. This is known as "conditional branching". Programming also allows you to repeat given keystroke sequences a certain number of times. This is known as "looping". If you are interested in advanced programming features of XACT-11C, we suggest you obtain a copy of the "HP-11C Owner's Handbook and Problem Solving Guide" 6.1 Entering a Program into XACT-11C To begin entering a new program into XACT-11C, the calculator must be placed in Program mode by pressing the [P/R] function key. When in program mode, subsequent keystrokes are simply stored in the calculator's internal memory. The [P/R] key toggles between program and run modes. Keystroke Display Comment ================================================================ [P/R] 000- Program mode [P/R] (as before) Run mode. - 26 - When first entering program mode, the display shows the value 000. This represents the current program line number of the program you are entering. Line 000- is special in that it always represents the beginning of program memory. Let's enter a very simple program: Keystroke Display Comment ================================================================ [P/R] 000- Program mode [Prgm] 000- Clear program memory [Lbl] [ A ] 001- 42 21 11 Label begins program 1 002- 1 0 003- 0 [ENTER] 004- 36 4 005- 4 [ + ] 006- 10 [Rtn] 007- 43 32 Return from program [P/R] Run mode The program simply adds the numbers 10+4 and finishes. When XACT-11C is in program mode, the numbers to the right of the program line are a code which represents which key was pressed. The first digit of the number indicates the row and the second indicates the column of where the key is positioned on the XACT-11C screen. If you think of all the keystrokes on the calculator face as being in a table with 4 rows and 10 columns, each key can be identified as being in a certain row and column. For example the [ENTER] key is located in Row 3, Column 6. Thus in instruction line 03- the display contains the value 36. Likewise the [ + ] key is in row 1, column 10, so the display shows 10.] To run the program: Keystroke Display Comment ================================================================ [ A ] 14.0000 Program result. Be sure to use the [ A ] function key mapped to the number '1' on the PC keyboard, not the letter 'A' on the PC keyboard. 6.2 Labels In Programs There are 15 labels available in programming, 0-9 and A-E. The previous example used the label [ A ] to identify the beginning of the program. An alphabetic label is always used to begin a program. Both alphabetic and numeric labels can be used as labels within a program. Labels are also used as targets of [Gto] (go to) and [Gsb] (go to subroutine) instructions. Labels can also be used to separate programs in XACT-11C's memory; as a way of keeping multiple programs in memory at the same time, - 27 - although this is generally not necessary since programs may be saved as disk files. 6.3 Using Subroutines A program can call a subroutine from within the program when the [Gsb] instruction is used within the program. For instance, the instruction [Gsb] 5 will transfer control to the program instruction immediately following the instruction [Lbl] 5 contained elsewhere within the program. Control will transfer to the label that identifies the subroutine. Subroutines can "nest", that is one subroutine may call another which may call another, and so on. The maximum level of subroutine nesting is 4. 6.4 Returning from a Program or Subroutine The last instruction in a program must always be a [Rtn]. This tells the program to reset it's program line number to 000 (go back to the beginning) and stop executing. The [Rtn] instruction is also the last instruction in a subroutine. In this case, after the execution of the [Rtn] instruction, control is transferred back to the instruction following the subroutine call. 6.5 Entering Data and the Run/Stop Key There are generally 2 ways to get data into a program. The easiest is to use the [Sto] instruction to store data in registers prior to running the program. Then the program can contain [Rcl] instructions to fetch the data from the register. The second method is required when there is more data to be input than available storage registers. It involves using the [R/S] (run/stop) function key. When this key is encountered during program execution, the program stops. At this point, you can enter new data and then press the [R/S] key. The program will begin running again. Let's write a program to solve the equation z= 1/(x+y) using the [R/S] key to allow us to enter both the x and y variables. Keystroke Display Comment ================================================================ [P/R] [Prgm] Clear program memory - 28 - [Lbl] [ A ] 001- 42 21 11 Beginning of program [ENTER] 002- 36 x value [R/S] 003- 31 Stop to accept y value [ + ] 004- 10 Add x + y [1/x] 005- 15 Invert [Rtn] 006- 43 32 End of program [P/R] Return to run mode. Now, to execute the program where x= 3 and y= 4: Keystroke Display Comment ================================================================ 3 [ A ] 3.0000 Waiting for y input. 4 [R/S] 0.1429 Result 6.6 The [Goto] Instruction The [Gto] instruction can be used to unconditionally jump to a location in the program identified with a [Lbl] instruction. For example, let's write a program that will keep track of the sum of the squares of a group of numbers we wish to enter. Keystroke Display Comment ================================================================ [P/R] [Prgm] Clear program memory [Lbl] [ A ] 001- 42 21 11 Beginning of program 0 002- 0 [ENTER] 003- 36 Clear x register [Lbl] 2 004- 42 21 2 Label used for looping [R/S] 005- 31 Stop to accept input [x^2] 006- 43 11 Square the input value [ + ] 007- 10 Add to sum of squares [Gto] 2 008- 22 2 Branch to label [P/R] To calculate the sum of the squares of 3, 7, 11, and 15: Keystroke Display Comment ================================================================ [ A ] 0.0000 Waiting for 1st value 3 [R/S] 9.0000 7 [R/S] 58.0000 11 [R/S] 179.0000 15 [R/S] 404.0000 6.7 Branching Using the Index Register In the previous example, we used a [Gto] instruction to branch to a label, in this case, label 2. As previously mentioned, there - 29 - are 15 available labels, 0-9 and A-E. You can also use the index register [I] to indirectly branch to a label, or indirectly call a subroutine. If the [I] register contains a number representing a label, the instructions [Gto] [I] and [Gsb] [I] will indirectly branch to a label or indirectly call a subroutine. 6.8 Program Loops Using the Index Register XACT-11C contains 2 instructions that first increment or decrement a special value contained in the index register and either execute or skip the next program line depending upon the condition met. These instructions are [Isg] (increment and skip if greater), and [Dse] (decrement and skip less than or equal). They can be used to control loops where the number of times to execute the loop is contained in the index register. Looping with the index register requires placing a special "coded value" in the index register. This value is of the form: aaaaa.bbbcc In the encoding, aaaaa represents a starting value of a loop counter and will default to 0 if it is not included. This value is incremented or decremented each time the flow of execution of the program encounters an [Isg] or [Dse] instruction respectively. The value contained in aaaaa is then compared against the value in bbb. In the case of the [Isg] instruction, if the value aaaaa is greater than bbb, the instruction in the program code which follows the [Isg] instruction will be skipped, and program execution will begin immediately following the skipped instruction. Likewise in the case of the [Dse] instruction, if the value aaaa is less than or equal to the value bbb, the same skipping over event will occur. In the encoding, the value cc represents the count to increment or decrement by each time the loop is executed. For example, if we wanted to execute a group of instructions within a loop 10 times where the loop counter begins at 10, and decrements by steps of 1 until it reaches 0, we would place the value 10.00001 in the index register. Notice that in the encoding, aaaaa= 10, bbb= 000, and cc= 01. A program fragment using this loop is shown below: 10.00001 [Sto] [ I ] [Lbl] [ A ] (Instructions within loop) [Dse] [Gto] [ A ] (Instructions after loop) - 30 - 6.9 Program Loops and Branches Using the X and Y Registers XACT-11C can also make "conditional tests" based upon values contained in the X and Y registers. There are 8 different possible conditions in all. These functions each execute the next instruction in the program if the condition is true, and skip over it if the condition is false. The instructions are defined as: [x<=y] true if x less than or equal to y [x<0] true if x less than 0 [x>y] true if x greater than y [x>0] true if x greater than 0 [x<>y] true if x not equal to y [x<>0] true if x not equal to 0 [x=y] true if x equal to y [x=0] true if x equal to 0 6.10 Branching On Flags Set/Clear XACT-11C contains two flags which can be set (1) or cleared (0) and then may be later tested and a conditional jump may occur depending on the state of the flags. The flags are Flag 0 and Flag 1. The flags are set or cleared with the [SF] or the [CF] function keys respectively. To set flag 1, for example, you would press [SF] 1. You may test the status of a flag with the [F?] function key within a program. Again, follow this key with either 0 or 1 depending on which flag you wish to test. If the flag was set, the instruction in memory immediately following the [F?] will be executed. If not, the program will skip over this instruction line number and proceed with execution at the next line number. The example below illustrates a program fragment utilizing flags testing: (Program instructions) [Lbl] 3 [SF] 0 [Gto] B (Program instructions) [Lbl] 4 [CF] 0 [Gto] B (Program instructions) [Lbl] B [F?] 0 (test to see if flag 0 is set) - 31 - [Gto] C (transfer control to label C if flag 0 set) [Gto] D (transfer control to label D if flag 0 clear) If the program executes at label 3, flag 0 is set and control is transferred to label B. At this point, since flag 0 was set, control will transfer to label C. Similarly, if the program executes at label 4, flag 0 is cleared, and thus, when control is transferred to label B, the flag test will fail. This will cause the [Gto] D instruction to be executed. 6.11 The Single-Step Instruction The [SST] (single-step) instruction can be used in either program mode or run mode. In program mode, pressing [SST] will display the next program line number in a program. In run mode, the [SST] function can be used to execute a program one step at a time. This is useful for program debugging. The [BST] (back- step) instruction works like the [SST] instruction in program mode except that it displays the previous program line number in a program. The [BST] instruction does not operate in run mode, that is, it won't back-step execution of a program, only display the previous program line number. 6.12 Moving to a Program Line Number You can move to a specific line number in either program mode or run mode. Press [Gto] [.] nnn where nnn is a 3 digit number between 0 and 203. In run mode, pressing [R/S] will begin execution at that line number. 6.13 Inserting and Deleting Program Lines XACT-11C can edit an existing program by inserting or deleting lines within the program. To do this, you must be in program mode and move to the line number where you wish to make the insertion/deletion using the [Gto] [.] nnn instruction where nnn is the line number (described ] in section 6.12 above). To insert a line, simply enter the instruction for the line you wish to insert. The insertion will happen immediately following the line and all other line numbers will be pushed ahead in memory. To delete a line, move to the line you wish to delete and press the [<-] function key. - 32 - 7. STATISTICAL CALCULATIONS XACT-11C can perform common statistical calculations including mean and standard deviation using it's built-in capabilities. In addition, programs can be written to perform complex statistical analysis. 7.1 Entering and Removing Numbers. The [S+] (shown as a Greek "sigma" character followed by '+' on XACT-11C) function key is used to enter a new number into the statistical registers. XACT-11C can be used to perform statistical operations using both one and two variables. When using one variable, that variable is referred to as the X variable. With two variable analysis, the second variable is referred to as the Y variable. When entering single variable numbers, enter the number and then press the [S+] function key. Continue this process until all numbers have been entered. With two variables, first key in the Y variable and press the [ENTER] key, then enter the X variable and press the [S+] key. When the [S+] function key is used, memory registers 1 through 6 will hold intermediate values. You can use the [Rcl] function key to view these values, or to use them within a program. The values contained in registers 1 through 6 are summarized below: R0 contains the value N, the number of data values (or data pairs) entered thus far. R1 contains the sum of all the X variable values. R2 contains the sum of the squares of all the X variable values. R3 contains the sum of all the Y variable values. R4 contains the sum of the squares of all the Y variable values. R5 contains the sum of the products of the X variable values and the Y variable values. To remove an incorrectly entered value, you can use the [S-] function key. Simply re-enter the incorrect value and then press the [S-] function key. 7.2 Statistical Mean Example: Suppose you are a teacher with 5 students. Student's scores on their last test were 80, 63, 77, 94, and 79. Find the mean of the test results. - 33 - Keystroke Display Comment ================================================================ [S] Clear statistics 80 [S+] 1.0000 1st score 63 [S+] 2.0000 2nd score 77 [S+] 3.0000 3rd score 94 [S+] 4.0000 4th score 79 [S+] 5.0000 5th score [xbar] 78.6000 Mean The mean of the test scores is 78.6. 7.3 Standard Deviation XACT-11C can be used to calculate the standard deviation of both x and y variables using the [S] function key. Example: Assume a set of students test scores for math and English tests are as follows: Student Math English ================================= 1 59 64 2 66 69 3 88 82 4 70 51 Calculate the standard deviation for the students results. Keystroke Display Comment ================================================================ [S] Clear registers 59 [ENTER] 64 [S+] 1.0000 1st student 66 [ENTER] 69 [S+] 2.0000 2nd student 88 [ENTER] 82 [S+] 3.0000 3rd student 70 [ENTER] 51 [S+] 4.0000 4th student [S] 12.8193 Math standard deviation [x<>y] 12.3659 English std. deviation The standard deviation for the student's math scores was 12.82 and for the English scores was 12.37. 7.4 Linear Estimate Using values entered for x and y variables, you can compute a "best guess" for either variable, given a sample value for the other one. Example: Using the above data for student test scores, compute an estimate for a student's English score given that the student - 34 - has a math score of 80. Compute the correlation coefficient for this value. Keystroke Display Comment ================================================================ 80 [y,r] 78.8692 Math score estimate [x<>y] 0.6235 correlation coefficient 7.5 Linear Regression Linear regression is a method used for determining the "best fit" straight line equation for a set of paired statistical data. XACT-11C can determine the factors for the equation Y= MX + B where M is the slope of the line and B is the Y intercept. The [L.R.] function key returns the slope M in the Y register and the intercept B in the X register. Keystroke Display Comment ================================================================ [L.R.] 30.7556 Y intercept [R|] 0.6014 Slope - 35 - 8. APPENDIX 8.1 Error Conditions When an error is encountered during operation, XACT-11C will display the word "Error" in the calculator's display, followed by a 1 digit error code. These error codes are defined below: Error 0 - Invalid math operation. This error is encountered when an operation attempted division by 0, the square root of a negative number, or other invalid operation. Error 1 - Out-of-Bounds Storage register operation. This happens if a storage register operation overflows the range of the calculator. Error 2 - Invalid Statistical operation. This happens if a statistical operation cannot be performed or is out of range, for instance taking the mean of 0 numbers. Error 3 - Invalid Register. An attempt was made to access a label or line number that is out of range. Error 4 - Invalid label or line number. An attempt was made to access a label or line number that is out of range. Error 5 - Invalid subroutine nesting. A subroutine was nested more than 4 levels deep. Error 6 - Invalid flag accessed. An invalid flag was accessed, valid flags are 0 and 1. - 36 -