VisualPQL Procedures homecontents start chapter top of pagebottom of pagenext page indexDescriptive

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 [,seed ] ]
                       [ / 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 special 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 should normally be 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 should consist 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 (which will be 0-2000,2000-4000,4000-6000): 
      DESCRIPTIVE  VARIABLE = SALARY /
                   RANGE = (3,0,6000)

SAMPLE Specifies that a random sample of the procedure table records are 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.
The optional seed is an integer that is used to initialise the random number generator.
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 SIR2002 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

ValuesFrequency
1000 - 15001
1500 - 20000
2000 - 25003
2500 - 30005
3000 - 35002
3500 - 40000
4000 - 45001
4500 - 50000

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

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