The World of Computer Software/World_Of_Computer_Software-02-385-Vol-1of3.iso/e/estat21.zip/EASIDOC.ZIP/ESCHAP08.DOC

Text File | 1992-06-30 | 13KB | 463 lines

     Chapter 8: SPECIAL COMMANDS


     8:1. Help

     Format: H[elp]

     The HELP command simply outputs a list of all the
     commands available, together with a brief reminder of
     their syntax. You may want to use the OUTPUT PRN command
     to print this list out on paper so you can refer to it
     when you do not have the manual handy.

     Examples:

     Select command -  help

     Select command -  o prn
     Select command -  h
     Select command -  o close

     Outputs list of commands to printer.

     Output:

     Help                               Titles
     Basics [G] [ranks] col [if cond]   Data [save] [filename]
     List [if cond or Variables]        Chisq [G] [Fish] [Num] [c r]
     Wilcoxon [S] [col]                 Ttest [paired]
     Anova [G or N] [col]               Kendall's [col col]
     Kolmogorov [G] [col]               Regress [G] [col col [col]]
     Multiple regression [col [col]]    Component analysis [G]
     Minimise [expression]              Narrow cond
     Widen [cond]                       Arithmetic [expression]
     New [col or row or next]           Label [col [name]]
     Format [col or def [width dec]]    Derive [col [expression]]
     Delete [col or row or all]         Echo
     Input [filename or close]          Output [filename or close]
     Log [filename or close]            Edit
     Screen                             Sort [d[own]] [col]
     Pause                              System [command]
     Limits [cl]                        Copy [lc,tr,rc,br,new lc,new tr]
     Macro [list or label exp]          Quit


     8:2. System

     Format: Sy[stem] [command or program]

     This allows you to issue DOS commands to the operating
     system or even run other programs, provided there is
     enough memory available. The commands specified are
     exactly what you would type at the DOS prompt and
     EASISTAT will pass them on unchanged.

     Example:

     Select command - sys dir

     Produces a list of files in the current working
     directory.


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     Select command - sys time

     Allows you to change the clock.

     Select command - sys edit command.log

     Runs the EDIT program to edit a file called COMMAND.LOG.

     When the command has been executed then EASISTAT will
     pause and wait for a keypress before continuing (unless
     it is being run from a command file).

     Comments

     You can use this command to list directories to remind
     yourself of the names of files you wish to use, or you
     can delete old output files before writing to a file with
     the same name. You can run a test editor to edit files
     and then automatically return to EASISTAT when you have
     finished without having to reload the program or read in
     data again. Do not however attempt to edit a file that is
     currently in use by EASISTAT, e.g. a command file that it
     is in the middle of reading.

     EASISTAT remains loaded in memory while the command is
     performed, so there will not be as much memory available
     to the second program as usual and if the second program
     needs a large amount of memory it may not be able to run.
     Do not run a memory resident or pop-up program using this
     command because it will stay in memory and may prevent
     EASISTAT from accessing memory which is in fact free.
     Pop-up programs (such as EASIMATH) should be run before
     EASISTAT is loaded.

     If you are familiar with DOS you will probably realise
     that instead of a program name one can actually enter
     SYSTEM COMMAND and run another copy of DOS from
     COMMAND.COM. Then many commands and programs can be
     executed before finally returning to EASISTAT. When you
     do wish to return to EASISTAT after doing this, enter
     EXIT.

     Because of the way DOS works it is not possible to
     permanently change any "environment variables" from
     within EASISTAT. This means that the DOS commands SET,
     PROMPT and PATH will not have any effect if used from
     within EASISTAT from the SYSTEM command. For example the
     following line will not actually change the DOS search
     path:

     Select command - sys set path=c:\utils

     If it is desired to change any environment variables in
     this way then it is necessary to first quit EASISTAT.
     This applies also to setting the FG_DISPLAY variable used
     to inform EASIGRAF of the type of display in use.







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     8:3. Screen

     Format: S[creen]

     This simply redraws the EASISTAT screen if an error has
     occurred which has messed it up.

     Example:

     Select command -  scr


     8:4. Arithmetic

     Format: Ar[ithmetic] [expression]

     This command evaluates arithmetical and logical
     expressions. Any such expression can be entered. If a
     calculation is entered on the first line then it is
     evaluated and the ARITHMETIC command finishes. If no
     calculation is entered then EASISTAT will request one,
     and will remain within the ARITHMETIC command until a
     blank line or error is encountered.








































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     Examples:

     Select command - ARITH
     Enter calculation:   5 +5*38
     Enter calculation:   2.6/7+(3.5-.6)pow(0.5)

     Select command - ar 5 +5*38

     One can use the probability look-up functions, e.g. to
     find the significance of a chi-squared of 13.6 with 2
     degrees of freedom:

     Select command - ARITH 13.6PX2

     If a column is specified then the value in the first
     valid row is used. This means that an arithmetic command
     can be put in an input file and used to carry out
     manipulations of variables which are entered into the
     first row:

     Select command - ar
     Enter calculation:   c1 pow(1/3)

     This outputs the cube root of the value in the first
     column in the first valid row of the table.

     Often it is convenient to have formulae contained in a
     command file such as this:

     e Normal approximation to binomial distribution
     e
     der v1 %1
     der v2 %2
     der v3 %3
     e Observed value is:
     ar v1
     e Total number of trials is:
     ar v2
     e Expected ratio is:
     ar v3
     e One-tailed p value (with continuity correction):
     ar 1-pn((abs(v1-v2*v3)-0.5)/((v2*v3*(1-v3))pow(0.5)))
     i close

     This calculates an approximation to a binomial
     probability of an observed event occurring x times out of
     n trials if the chance of such an event occurring on each
     trial is p. If the command file name is BINOM it can be
     run as follows:

     Select command -  INPUT BINOM 12 15 0.4

     Here x is 12, n is 15 and p is 0.4.

     Here's another file to solve quadratic equations. The
     three coefficients are passed as parameters to the file:

     Select command -  INPUT QUAD 3 5 1

     Command file QUAD contains the following lines:



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     der v1 %1
     der v2 %2
     der v3 %3
     e Solving quadratic equation with following coefficients:
     ar
     v1
     v2
     v3
     ((v2*v2-4*v1*v3)pow0.5-v2)/(2*v1)
     (0-(v2*v2-4*v1*v3)pow0.5-v2)/(2*v1)

     ; blank line above to finish arithmetic command
     i close

     With coefficients 3, 5 and 1, these formulae find roots
     at -0.232 and -1.434.

     Using this kind of technique one can build up a
     collection of command files for evaluating different
     expressions and can use EASISTAT like a programmable
     calculator. If the number output is very large or very
     small then it will be output in exponential notation
     (described in the section on arithmetic expressions).


     8:5. Macro

     Format: Ma[cro] [list or name expression]

     This allows you to produce abbreviations of complicated
     expressions so that you can refer to them more succintly.
     The macro can thereafter be incorporated in other
     expressions in the same way as a value or variable. This
     facility is indispensable when dealing with complicated
     mathematical formulae, although it is true that its
     usefulness is somewhat limited by the inability to pass
     any arguments to the expression. Here is an example where
     we define a macro QUAD to evaluate a quadratic expression
     with the first three variables as coefficients and the
     fourth as the value to use, then we define macros SOLP
     and SOLM to be the roots based on the positive and
     negative square roots in the formulae above. Then we can
     assign different values to the four variables and
     instantly compute the related values for quadratic QUAD,
     SOLM and SOLP.

     Select command - mac quad v1*v4*v4 + v2*v4 + v3
     Select command - mac solp ((v2*v2-4*v1*v3)pow0.5-v2)/(2*v1)
     Select command - mac solm (0-(v2*v2-4*v1*v3)pow0.5-v2)/(2*v1)
     Select command - der v1 3
     Select command - der v2 5
     Select command - der v3 1
     Select command - der v4 1
     Select command - ar quad
     Select command - der v4 2
     Select command - ar quad
     Select command - der v4 3
     Select command - ar quad
     Select command - ar solp
     Select command - ar solm
     Select command - der v4 -0.232
     Select command - ar quad

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     Select command - der v4 -1.434
     Select command - ar quad

     The quadratic function is evaluated with V4, the fourth
     general purpose variable, set to values of 1, 2 and 3 and
     then the two roots are found. Then V4 is set equal to
     each of the roots and the function is again evaluated.
     Each time the result is close to zero, confirming that
     the correct values for the roots have been calculated.

     Here is another example of a macro which yields the
     maximum of the values in the first three columns:

     Select command - macro max2 c1*(c1>c2)+c2*(c2>=c1)
     Select command - macro max3 c3*(c3>max2)+max2*(max2>=c3)

     This first defines a macro MAX2 which is the maximum of
     the first two columns, then uses this macro to define
     MAX3, the maximum of the third column and MAX2. The macro
     can then be used freely in subsequent expressions, e.g.:

     Select command - der c5 7.2+max3*c4

     Macros can be nested in this way, and complicated
     mathematical expressions can be built up. The same rules
     apply to naming macros as apply to labelling columns and
     variables - please refer to these if you have problems,
     especially with syntax errors. Macros already defined can
     be listed with the key word LIST (which cannot be
     abbreviated) instead of a macro name:

     Select command - macro list


     8:6. Limits

     Format: Lim[its] [value]

     Specifies a value for confidence limits to be output by
     the BASICS, REGRESS and TTEST commands. The value
     specified must be between 5 and 99.9 and is a percentage.
     If a value of 0 is specified then confidence limits will
     no longer be calculated.

     Example:

     Select command -  lim 95

     From now on 95% confidence limits will be calculated
     where appropriate.

     Calculating confidence limits can slow down the
     performance of EASISTAT so this is only done if
     specifically requested by the LIMITS command.
     Alternatively the command line switch /L can be used when
     EASISTAT is first run:

     EASISTAT /L95





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     8:7. Quit

     Format: Q[uit]

     Quits EASISTAT and returns control to the DOS command
     line or the batch file from which EASISTAT was run.

     Example:

     Select command -  q
     Quit EASISTAT        - ALL UNSAVED DATA WILL BE LOST -
     Sure?
     y

     Confirmation that you really do wish to leave EASISTAT is
     requested, so if you wish to have a command file which
     does quit EASISTAT at the end, the line containing the
     QUIT command must be followed by a line saying YES or Y.













































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