17.5.3 Paired-Sample Sign Test
Introduction
The paired-sample sign test is a non-parametric alternative to the paired-sample t-test. It is frequently used to test the effect of a treatment on a group of subjects. The data must be paired measurements (for example, "before" and "after" data resulting from a clinical trial).
Unlike the paired-sample t-test, the paired-sample sign test does not require the assumption of normality. Thus, when normality is questionable, the paired-sample sign test can be used in place of the paired-sample t-test.
Handling Missing Values
If there are missing values in the data range, the whole pair will be excluded in the analysis
Performing Paired-Sample Sign Test
To perform a paired-sample sign test:
- Select Statistics: Nonparametric Tests: Paired-Sample Sign Test. This opens the sign2 dialog box.
- Specify the Data Range, and the Alternate Hypothesis.
- Upon clicking OK, an analysis report sheet is generated showing the frequency table, degrees of freedom, the S and Z statistics, the associated p-value, and the test conclusion.
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