The UNIVARIATE Procedure

An instructor is interested in creating a frequency table of score changes between a pair of tests given in one of his college courses. The data set Score contains test scores for his students who took a pretest and a posttest on the same material. The variable ScoreChange contains the difference between the two test scores. The following statements create the data set:

data Score;
   input Student $ PreTest PostTest @@;
   label ScoreChange = 'Change in Test Scores';
   ScoreChange = PostTest - PreTest;
   datalines;
Capalleti  94 91  Dubose     51 65
Engles     95 97  Grant      63 75
Krupski    80 75  Lundsford  92 55
Mcbane     75 78  Mullen     89 82
Nguyen     79 76  Patel      71 77
Si         75 70  Tanaka     87 73
;

The following statements produce a frequency table for the variable ScoreChange:

title 'Analysis of Score Changes';
ods select Frequencies;
proc univariate data=Score freq;
   var ScoreChange;
run;

The ODS SELECT statement restricts the output to the "Frequencies" table; see the section ODS Table Names. The FREQ option in the PROC UNIVARIATE statement requests the table of frequencies shown in Output 4.4.1.

From Output 4.4.1, the instructor sees that only score changes of and occurred more than once.

A sample program for this example, uniex03.sas, is available in the SAS Sample Library for Base SAS software.