This example demonstrates a sign test for paired data, which is a specific application of the tests for location discussed in Example 4.12.
The instructor from Example 4.4 is now interested in performing a sign test for the pairs of test scores in his college course. The following statements request basic statistical measures and tests for location:
title 'Test Scores for a College Course'; ods select BasicMeasures TestsForLocation; proc univariate data=Score; var ScoreChange; run;
The ODS SELECT statement restricts the output to the "BasicMeasures" and "TestsForLocation" tables; see the section ODS Table Names. The instructor is not willing to assume that the ScoreChange
variable is normal or even symmetric, so he decides to examine the sign test. The large p-value (0.7744) of the sign test provides insufficient evidence of a difference in test score medians.
Output 4.13.1: Sign Test for ScoreChange
Test Scores for a College Course |
Basic Statistical Measures | |||
---|---|---|---|
Location | Variability | ||
Mean | -3.08333 | Std Deviation | 13.33797 |
Median | -3.00000 | Variance | 177.90152 |
Mode | -5.00000 | Range | 51.00000 |
Interquartile Range | 10.50000 |
Note: The mode displayed is the smallest of 2 modes with a count of 2. |
A sample program for this example, uniex03.sas, is available in the SAS Sample Library for Base SAS software.