The World of Computer Software/World_Of_Computer_Software-02-385-Vol-1of3.iso/e/estat21.zip/EASIDOC.ZIP/ESCHAP07.DOC

Text File | 1992-06-30 | 21KB | 661 lines

     Chapter 7: FILE MANAGEMENT COMMANDS


     7:1. Data

     Format: D[ata] [s[ave]] [filename or THIS]

     This command reads in data from a file with the name
     given, or if the keyword SAVE (which can be shortened
     down to S) is used first the data is written to the file.
     The data file is simply a text file containing a table of
     numerical values arranged in columns beneath one row of
     titles which determines the width of each column. The
     titles consist of groups of letters or numbers separated
     by spaces. There must be no blank rows in the table.
     Titles and values must be separated by spaces and not
     tabs. If a blank row or one beginning with the word END
     is found then that will be taken as the end of the data.
     This format should make it possible to transfer data
     between EASISTAT files and files used by other software,
     including spreadsheets, databases and word processors.

     Example data file:

     Age Sex GHQ
     20   1  12
      29 2    13
     22  2   14
     end

     "End" is optional if that is the end of the file or if a
     blank line appears instead. The start of each column
     position is defined by the left-most letter of each label
     (A,S,G). The end of each column is defined by the start
     of the next one. The end of the last column is defined by
     the end of the title line, so if any data values extended
     beyond the end of the first line they would not be read
     in correctly (for example if 13 was replaced by 135
     above, it would be read in as 13 because the 5 would be
     truncated). To prevent this happening extra spaces can be
     added to the end of the title line and these spaces would
     be included as part of the width of the last title. This
     is done automatically by EASISTAT when data files are
     saved. Any blank values will be taken as zero.

     Examples:

     Select command -  DATA EXAMPLE.DAT

     Reads in data from file EXAMPLE.DAT.

     Select command -  d s fixed.dat

     Saves data in a file called FIXED.DAT. When the data set
     has been narrowed down (with the NARROW command) then
     only the valid rows will be saved.

     Select command -  DATA THIS

     Using the keyword THIS causes the data to be read from
     the current input stream. If you are using EASISTAT from
     the keyboard you can type in data as it would appear in a

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     file. If it is being run by a command file using the
     INPUT command then the data can be included as part of
     the input file. It is terminated by a blank line or the
     keyword "END". This allows you to keep data in one file
     immediately followed by the commands to produce and
     derive new columns, and to run the desired statistical
     tests on the data.

     Example command file to input and modify data:

     DATA THIS
     age sex beauty
     26   1   2
     31   2   5
     16   2   9.5
     end
     NEW c4 CODE
     DERIVE c4 1*(AGE<20) + 2*((AGE>=20)&(AGE<40)) + 3*(AGE>=40)
     DERIVE c4 c4*SEX

     If this file is called DATAFILE it is read in with the
     INPUT command:

     Select command - INPUT DATAFILE

     (not DATA DATAFILE, the DATA command occurs within
     DATAFILE). Here the DERIVE command is used to combine AGE
     and SEX to produce a new variable called CODE.

     Output:

     Widening data set to include all lines

     If a NARROW command had been issued before the data is
     read in then it now ceases to apply.

     To produce a suitable data file from a word processor
     just type out the data in columns as described above,
     then save it to disk. If your word processor has an
     option to save the text as "ASCII" or "DOS text" or "non-
     document" then you must use this option. The EDIT.EXE
     program supplied is a simple text editor which can be
     used for creating and editing EASISTAT data files. Also,
     if you have any problems reading a file with the DATA
     command it would be helpful to use EDIT.EXE to study it
     to see what might be causing the problem, for example any
     special formatting characters that a word processor may
     have introduced.

     To produce a suitable data file from Lotus 1-2-3:

     1. Select "Print", select print to "File".

     2. Select the entire range of values as the "Range" to be
     printed, with a one line set of titles above if you have
     one. There must be a title line above the values in the
     data file, so if you do not print one out from 1-2-3 then
     you must add one yourself with a word processor
     afterwards.




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     3. Select "Options".

     4. Select margins and set "Left" margin to 0 and "Right"
     to 240.

     5. Select "Other". Select "Unformatted" output.

     6. Go back to print (by selecting "Quit") and select
     "Go".

     Warning

     EASISTAT does not make any automatic backups and does not
     warn you if you are going to over-write an existing file.
     Saving to the same file as the data was originally in may
     be dangerous, since if you have made a mistake then the
     original data will be lost. Unless you can be sure always
     to specify a new filename with DATA SAVE, it is wise to
     make a copy of your data file under another name or onto
     another disk. You can do this before entering EASISTAT by
     using the DOS command COPY, or while using EASISTAT by
     using the SYSTEM COPY command to back up your data, e.g.:

     Select command -  system copy origdata.dat bkupdata.dat


     7:2. Output

     Format: O[utput] [filename or close]

     The OUTPUT command copies all of the output from EASISTAT
     that appears in the top window of the screen to a file or
     to the printer. This allows you to save your results and
     study them later, and means you can use a word processor
     to incorporate them into a document without having to
     type them all in again. When you no longer wish to send
     output to the file the OUTPUT CLOSE command closes the
     file and no further output is copied. OUTPUT writes on to
     the end of a file, so if you choose to write to a file
     which already exists whatever was previously in that file
     will be left as it is and the new results will be tagged
     on at the end. If you have a printer hooked up to your
     computer you should be able to print out to it directly
     by typing OUTPUT PRN.

     Examples:

     Select command -  OUTPUT ANOV0924.OUT

     This command copies output into the file ANOV0924.OUT. If
     the file does not exist then it will be created. If it
     already exists then the new output will be appended to
     the old file.

     Select command -  OUTPUT
     Enter name of file to write output to: ANOV0924.OUT

     If you do not initially supply a filename, you will be
     prompted for one.




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     Select command -  OUTPUT PRN

     From now on all the results will be sent to directly to a
     printer if you have one connected. PRN is the special
     MSDOS name for the printer. Make sure your printer is
     switched on, connected and "on line" before you use this
     option. If it does not work it may be because your
     printer is not connected to the first parallel port of
     your computer. If this is so, instead of PRN try using
     LPT2, COM1 or COM2. Consult your DOS manual for details
     and see the section on error messages.

     Select command -  OUTPUT CLOSE

     Output will no longer be copied to the file or printer
     until another OUTPUT command is given.

     Example output:

             ********************************
             *                              *
             *     Output from EASISTAT     *
             *     (C) ARC Scientific 1989  *
             *                              *
             ********************************

     This is the first thing OUTPUT will send to the results
     file if it is a new file. If the file already exists only
     new results will be copied onto the end of it.

     Comments

     If you use the OUTPUT command to write to a second file
     when another one is already being written to then the
     first file will be closed and the second file used
     instead. You cannot write to two files at once, or to a
     printer and a file at the same time.

     We recommend that you make extensive use of the ECHO
     command to provide titles and comments in your output
     file so that when you refer to it later you will be able
     to remember what each test was supposed to do. See the
     section on the ECHO command.

     Using OUTPUT for printing results

     Although it is possible to print off results straight
     away using PRN as the filename, in general we would
     recommend that you should send the results into a file
     instead and then use a word processor, the EDIT.EXE
     program or the DOS PRINT command (see your DOS manual) to
     print off the file when you have finished using EASISTAT.
     If you have the results saved in a file on disk then you
     have a permanent record which can be printed off as many
     times as you like, and in addition you can edit them and
     incorporate them directly into a larger document without
     onerous retyping.






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     7:3. Input

     Format: I[input] [filename [param1 param2 ....] or close]

     Causes a command file to be read in. Command files
     contain commands exactly as they would be typed at the
     keyboard.

     Examples:

     Select command - IN COMM0911.LOG

     Select command -  i
     Enter name of file to read input from (KEY for keyboard):
     demo

     If you do not initially supply a name for the file then
     EASISTAT will ask for it.

     Select command -  i close

     The keyword CLOSE means finish the command file now, as
     if the end of the file had been reached.

     It is also possible to pass replaceable parameters to a
     command file as one can with DOS batch files. These
     parameters are typed on the EASISTAT command line after
     the file name, and are then substituted wherever %1, %2
     ... %10 appear in the command file. If you have an input
     file called EXAMPLE that contains the following line:

     ECHO parm1 %1 parm2 %2 parm3 %3

     then entering:

     Select command -  INPUT EXAMPLE one two testing

     will produce the following output:

     parm1 one parm2 two parm3 testing

     The original purpose of this was to allow you to perform
     the same set of tests repeatedly on different columns,
     but it is a very flexible feature and can be used in a
     variety of other ways as well.

     Comments

     Command files are a powerful feature of EASISTAT. Long
     and complex analyses can be prepared in advance on a word
     processor and then can be run automatically without
     supervision. As you grow more familiar with EASISTAT you
     shold learn to use command files extensively.

     The file on your disk called DEMO is a command file.
     Please study it to see how it works. Note that you can
     also input a command file when you first run EASISTAT by
     entering e.g. EASISTAT DEMO. This causes EASISTAT to read
     in the command file called DEMO, exactly as if you had
     typed INPUT DEMO instead once EASISTAT was running. This
     facility means EASISTAT analyses can be run as part of
     DOS batch files (in fact the demonstration is usually run

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     by a batch file called DEMO.BAT Which contains the line
     EASISTAT DEMO).

     Normally if EASISTAT finds an error in a command file it
     will pause and ask whether to continue or jump to the end
     of the file or relinquish control to the keyboard. You
     may want to prevent this happening and for EASISTAT to
     continue even if it does find errors, perhaps because you
     wish to perform some long analyses while the computer is
     unattended. To do this use the /I switch in the command
     line after the file name:

     EASISTAT A-LONG.JOB /I

     In this mode EASISTAT will not stop for errors or pauses
     in the command file. It may be wise to put a few blank
     lines between each command in the command file, so that a
     mistake in one does not cause the next to be misread.

     Normally when a graphing option is chosen for one of the
     EASISTAT commands the graph file will be written to disk
     and then EASIGRAF will be run automatically. However
     EASIGRAF is not run if a command file is being used,
     although the graph file is still written to disk.
     Similarly the usual pause does not occur after the
     execution of a SYSTEM command.

     Command files can be nested up to five deep, that is one
     command file can contain an INPUT command to read in
     another, and so on. The second will be read through and
     when it finishes control is returned to the first file.
     It is possible for a command file to transfer control
     temporarily to the keyboard as if the keyboard was
     another file. To do this the keyword KEY is used:

     INPUT KEY

     Since the keyboard doesn't end the way a file does, the
     only way to get back to the original file is to type:

     INPUT CLOSE

     Unless the /I switch has been used, every time the
     command file comes across the PAUSE command or an error
     is found the user is given the option of taking temporary
     control at the keyboard by typing K. He or she can later
     return to the command file by using the INPUT CLOSE
     command. A command file can also be made to pause between
     commands by pressing CONTROL-C or CONTROL-BREAK.

     Any line in an input file starting with a semi-colon is
     ignored. This can be used to put explanatory comments and
     reminders into input files.

     Here is an example of a fairly complex command file which
     takes the names of two columns as parameters and performs
     Wilcoxon's signed rank sum test to compare them. If the
     file were called WILCSR.INP then one would run it by
     entering:




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     INPUT WILCSR.INP C14 C15

     to compare columns 14 and 15.

     ECHO Command file "WILCSR" to perform signed rank sum test
     ECHO     comparing %1 and %2
     LABEL V1 N'
     LABEL V2 T1
     LABEL V3 T2
     LABEL V4 VAR
     LABEL V5 MEAN
     ; use convenient labels to refer to the first four general
     ; variables
     NEW NEXT DIF
     DERIVE DIF %1 - %2
     ; create a new column called DIF, the difference between the
     ; two columns to be compared
     NARROW %1 != %2
     ; ignore rows in which the values are equal
     DERIVE DIF ABS DIF
     DERIVE DIF RANK DIF
     ; alter DIF to contain the ranks of the absolute magnitudes
     ; of the differences between the columns
     BASICS DIF
     DERIVE N' XNUMBER
     BASICS DIF IF %1>%2
     DERIVE T1 XTOTAL
     BASICS DIF IF %1<%2
     DERIVE T2 XTOTAL
     ; now N' contains the number of rows used, T1 is the total of
     ; the ranks of the differences for which the first column is
     ; larger and T2 of those for which the second is larger
     DERIVE VAR N'*(N'+1)*(2*N'+1)/24
     DERIVE MEAN 0.25*N'*(N'+1)
     ECHO Here are the values for T1, T2 and N':
     ARITH T1
     ARITH T2
     ARITH N'
     ECHO Standardised normal deviate (with continuity correction) is:
     ARITH (ABS(T1-MEAN)-0.5)/(VAR POW 0.5)
     ECHO
     ECHO Approximate P value (single-tailed) is:
     ARITH 1-PN((ABS(T1-MEAN)-0.5)/(VAR POW 0.5))
     ; the expected mean and variance are used to calculate the
     ; standardised normal deviate and therefore significance of the
     ; result (ties are ignored)
     DEL DIF
     ; finally, the new column created is deleted

     The built-in Wilcoxon's signed rank sum test is somewhat
     superior to this command file because it takes account of
     tied ranks. However this example is designed to
     demonstrate the way in which additional statistical tests
     not built into EASISTAT can be constructed by hand if
     desired.

     Another way to use command files might be to set up some
     batch files which will run certain simple tests
     automatically. For example, the following batch file
     called CHISQ.BAT can be run from DOS to perform a two-by-
     two chi-squared test:


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     rem CHISQ.BAT
     if exist chisq.out del chisq.out
     echo output chisq.out > chisq.inp
     echo chisq n 2 2 >> chisq.inp
     echo %1 %2 >> chisq.inp
     echo %3 %4 >> chisq.inp
     echo quit >> chisq.inp
     echo y >> chisq.inp
     easistat chisq.inp
     type chisq.out

     This batch file uses the parameter substitution feature
     and ECHO command of DOS (not EASISTAT) to produce a
     command file for EASISTAT called CHISQ.INP. If the batch
     file were run from DOS as follows:

     CHISQ 6 12 34 10

     then CHISQ.INP would contain the following lines:

     output chisq.out
     chisq n 2 2
     6 12
     34 10
     quit
     y

     When EASISTAT is run the commands in CHISQ.INP are read
     in just as if the command INPUT CHISQ.INP had been given
     from within EASISTAT. These commands instruct EASISTAT to
     send its output to a file called CHISQ.OUT, then to
     perform a chi-squared test on a two-by-two table with the
     values specified, and then to quit and return to DOS.
     Control is thus returned to the batch file which uses the
     TYPE command to display CHISQ.OUT on the screen.


     7:4. Log

     Format: Lo[g] [filename or close]

     Produces command files by copying keyboard input to a
     file. This log file can then be read in again as a
     command file, or it can be edited and elaborated first.
     This is a very useful way to get started creating command
     files.

     All the commands typed in at the keyboard are copied into
     the file with the name specified, until the command is
     reissued with the filename CLOSE (which cannot be
     abbreviated). This provides a very useful record of the
     commands typed in during a session. It would then be
     possible to repeat exactly the same sequence of commands
     on another occasion just by using the INPUT command to
     read in the commands from the log file. Alternatively the
     file can be adjusted with a text editor such as EDIT.EXE
     before being read in again.






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     Examples:

     Select command - log stat0927.log

     Copies all commands into STAT0927.LOG.

     Select command - log close

     Closes file so that no further commands will be copied.
     Like the OUTPUT command, LOG writes onto the end of a
     pre-existing file.


     7:5. Echo

     Format: E[cho] text

     Echoes input to output, allowing comments and titles to
     appear in output files, or for command files to explain
     themselves on screen as they run.

     Example:

     Select command -  e    The title of the next test is this

     Everything on the line after the echo command is copied
     to the output, that is into the top window of the screen
     and into an output file if one has been opened. This is
     very useful for entering explanatory notes about the
     tests one is doing into an output file, because it may be
     quite hard when reading them later to work out what is
     going on.

     See the DEMO file for examples of the use of the ECHO
     command (the E at the start of most lines is invoking
     ECHO).


     7:6. Pause

     Format: P[ause]

     Produces a pause in a command file.

     Example:

     Select command -  p

     Output:

     A pause has occurred in the input command file
     'E' to end file, 'K' to use keyboard, any other key to continue

     The pause allows the user to read what has appeared on
     screen. It also gives him or her the chance to abort the
     command file, by pressing E, or to take temporary control
     of EASISTAT as if the INPUT KEY command had been issued,
     by pressing K. In the latter case he or she can return
     later to the command file (which remains open) by
     entering INPUT CLOSE (to finish keyboard input).



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     This command is ignored if EASISTAT has been run with the
     /I switch, which causes it to ignore errors and pauses.





























































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