PQL Procedures

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PQL Procedures

Descriptive

The DESCRIPTIVE procedure produces a frequency barchart and descriptive statistics on a numeric or short string (up to eight characters) variable. Frequency counts show how many times a variable had a particular value, or had a value which fell within a range.

     DESCRIPTIVE  VARIABLE = var
                       [ BOOLEAN = (log_expression) ]
                       [ FILENAME = ldi ]
                       [ HTML ]
                       [ INTERVALS = (n,n+,n++,...)]
                       [ RANGE = (categories,min,max)]
                       [ SAMPLE = sample]
                       [ STRINGS   = ('n','n+','n++',...)]
                       [ SUBTITLE = 'text' ]
                       [ TITLE    = 'text' ]
                       [ WEIGHT   = varname]

Specify a variable name. This produces a frequency table and counts of included observations (values in the frequency table) and missing observations (missing and undefined values) plus a set of descriptive statistics.

Default frequency ranges for numeric variables are calculated from the minimum and maximum values of observations. The number of ranges is taken from the square root of the number of observations with a minimum of seven and a maximum of fifty.
There are no default ranges for string variables and these must be specified as part of the STRING parameter.

BOOLEAN Specifies which procedure table records are used by the procedure. The procedure table records for which the logical expression is true are used by the procedure. If this option is not specified, all procedure table records are used.

FILENAME Specify the filename created by the procedure.
If no FILENAME clause is specified, the output is written to a default file sirdesc.srg.
If the filename CGI is specified then output is written to the user's internet browser if the procedure is run through the CGI interface. If this filename is used and the procedure is run when the CGI interface is not active, output is written to a file sircgi.htm. Output written to CGI is normally in HTML format (see below).

HTML Specifies that output is produced in HTML format suitable for viewing through a browser.

INTERVALS Specify a set of values, in increasing order, that represent the boundaries of the ranges in the frequency table. Values below the first and beyond the last value are omitted. For example, to create three ranges for Salary:
DESCRIPTIVE VARIABLE = SALARY / INTERVALS = (0,2000,3000,9999)
Cannot specify both INTERVALS and RANGES.

RANGE Specify that the frequency table consists of n ranges with the specified lowest and highest limits. Values below the first and beyond the last value are omitted. For example, to create three ranges for Salary (0-2000,2000-4000,4000-6000):
DESCRIPTIVE VARIABLE = SALARY / RANGE = (3,0,6000)

SAMPLE Specifies that a random sample of the procedure table records is used by the procedure.
The fraction specifies the percent of records used and is specified as a positive decimal number less than or equal to 1 (one). .25, for example specifies that a 25% sample be used.

STRINGS Specifies that the variable to be analysed is a string (up to eight characters in length) and the set of values to use for the frequency chart. Specify a set of values, in increasing order, that represent the boundaries of the ranges in the frequency table. Values below the first and beyond the last value are omitted. Note that descriptive statistics are not produced for strings.

SUBTITLE Specifies the text on the DESCRIPTIVE report footer. Enclose the text in quotes. If SUBTITLE is not used, the subtitle is "Created by SIR/XS on DATE at TIME".

TITLE Specifies the text on the DESCRIPTIVE report title. Enclose the text in quotes. If TITLE is not used, the title is the variable label or name when no label.

WEIGHT Specifies the procedure variable used as a weighting factor for the variables in FREQUENCIES. Normally, cell counts are incremented by one for each appropriate occurrence. When a weighting value is specified, the cell count is incremented by the value in the specified variable.
See examples.

Examples

Example 1

Produces a default analyses on Education Level (EDUC).

RETRIEVAL
PROCESS CASES
.  PROCESS REC EMPLOYEE
.    GET VARS EDUC
.    PERFORM PROCS
.  END REC
END CASE
DESCRIPTIVE VARIABLE   = EDUC
            FILENAME   = EDUC.SRG  /
            TITLE      = 'Education Levels in Company' /
END RETRIEVAL

On completion of the program, the file EDUC.SRG contains text which can be viewed with

ESCAPE 'sirgraph.exe educ.srg'

which looks something like:

Example 2

Produce a default analysis on salary.

RETRIEVAL
PROCESS CASES
.  PROCESS REC EMPLOYEE
.    GET VARS SALARY
.    PERFORM PROCS
.  END REC
END CASE
DESCRIPTIVE VARIABLE   = SALARY /
            FILENAME   = SALARY.SRG  /
END RETRIEVAL

On completion of the program, the file SALARY.SRG contains text which can be viewed with

ESCAPE 'sirgraph.exe salary.srg'

which looks something like:

Example 3

Analyse a string variable (name) by letter.

RETRIEVAL
STRING*4 SNAME
PROCESS CASES
.  PROCESS REC EMPLOYEE
.    COMPUTE SNAME = NAME
.    PERFORM PROCS
.  END REC
END CASE
DESCRIPTIVE VARIABLE = SNAME /
            FILENAME = NAMES.SRG  /
            STRING = ('A','E','I','O','U','Z') /
            TITLE        = 'Names in Company' /
END RETRIEVAL

On completion of the program, the file NAMES.SRG contains text which can be viewed with

ESCAPE 'sirgraph.exe names.srg'

which looks something like:

Example 4

Produce an analysis on salary in eight $500 bands between 1000 and 5000 and produce the output as html.

RETRIEVAL
PROCESS CASES
.  PROCESS REC EMPLOYEE
.    GET VARS SALARY
.    PERFORM PROCS
.  END REC
END CASE
DESCRIPTIVE VARIABLE  = SALARY
         RANGE = (8,1000,5000)
         FILENAME   = SALARY.HTM   HTML
END RETRIEVAL

On completion of the program, the file SALARY.HTM contains text which can be viewed with any browser which looks something like:

Frequencies Table for Current monthly salary

Values	Frequency
1000 - 1500	1
1500 - 2000	0
2000 - 2500	3
2500 - 3000	5
3000 - 3500	2
3500 - 4000	0
4000 - 4500	1
4500 - 5000	0

Frequency Bar Chart


1000 - 1500	1500 - 2000	2000 - 2500	2500 - 3000	3000 - 3500	3500 - 4000	4000 - 4500	4500 - 5000

Descriptive Statistics

Number of Observations	12.00
Number of Missing Observations	2.00
Mean	2702.83
Standard Deviation	678.84
Variance	460823.61
Minimum	1234.00
Maximum	4000.00
First Quartile	2337.50
Median	2725.00
Third Quartile	2962.50
Mean (95% C.I)	2271.52 - 3134.15
CV Percent	25.12
Skewness	-0.288310643
Kurtosis	1.7548682

`BOOLEAN`	Specifies which procedure table records are used by the procedure. The procedure table records for which the logical expression is true are used by the procedure. If this option is not specified, all procedure table records are used.
`FILENAME`	Specify the filename created by the procedure. If no `FILENAME` clause is specified, the output is written to a default file `sirdesc.srg`. If the filename `CGI` is specified then output is written to the user's internet browser if the procedure is run through the CGI interface. If this filename is used and the procedure is run when the CGI interface is not active, output is written to a file `sircgi.htm`. Output written to CGI is normally in HTML format (see below).
`HTML`	Specifies that output is produced in HTML format suitable for viewing through a browser.
`INTERVALS`	Specify a set of values, in increasing order, that represent the boundaries of the ranges in the frequency table. Values below the first and beyond the last value are omitted. For example, to create three ranges for Salary: DESCRIPTIVE VARIABLE = SALARY / INTERVALS = (0,2000,3000,9999) Cannot specify both `INTERVALS` and `RANGES`.
`RANGE`	Specify that the frequency table consists of n ranges with the specified lowest and highest limits. Values below the first and beyond the last value are omitted. For example, to create three ranges for Salary (0-2000,2000-4000,4000-6000): DESCRIPTIVE VARIABLE = SALARY / RANGE = (3,0,6000)
`SAMPLE`	Specifies that a random sample of the procedure table records is used by the procedure. The fraction specifies the percent of records used and is specified as a positive decimal number less than or equal to 1 (one). .25, for example specifies that a 25% sample be used.
`STRINGS`	Specifies that the variable to be analysed is a string (up to eight characters in length) and the set of values to use for the frequency chart. Specify a set of values, in increasing order, that represent the boundaries of the ranges in the frequency table. Values below the first and beyond the last value are omitted. Note that descriptive statistics are not produced for strings.
`SUBTITLE`	Specifies the text on the `DESCRIPTIVE` report footer. Enclose the text in quotes. If `SUBTITLE` is not used, the subtitle is "Created by SIR/XS on DATE at TIME".
`TITLE`	Specifies the text on the `DESCRIPTIVE` report title. Enclose the text in quotes. If `TITLE` is not used, the title is the variable label or name when no label.
`WEIGHT`	Specifies the procedure variable used as a weighting factor for the variables in `FREQUENCIES`. Normally, cell counts are incremented by one for each appropriate occurrence. When a weighting value is specified, the cell count is incremented by the value in the specified variable.