Wilcoxon Group Comparison

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Description:

The Wilcoxon group comparison in ChemStat follows the procedures in the U.S. Navy 1999 Guidance document. The test is a non-parametric test for comparing compliance measurements to background measurements. Because the test is non-parametric, normality is not required, and the test is suitable for a moderately large number of non-detects.

ChemStat performs the group comparison at 90%, 95%, 97.5%, and 99% levels of significance.

Use:

Use this method as a non-parametric method for comparing compliance measurements to background.

Remarks:

If the test is performed at the 97.5% or 99% level of significance, then the test is performed using the procedure for large data sets regardless of the sample size. This is because there are no adequate table values for these significance levels.