p -Value Combination Method

This feature enables you to specify a method for combining p-values in each analysis group.

P -Value Combination Method 1	Definition
minPvalue	• Takes the smallest p -value in the group and applies the Sidak correction to obtain the correct p -value
Fisher	• Replaces the p -value at the center of the sliding window with the p -value of the t-statistic .
Simes	• Replaces the p -value at the center of the sliding window with the p -value computed using Simes’ method 2 .
TPM	• Replaces the p -value at the center of the sliding window with the p -value computed using Zaykin’s method 3 . • The TPM is a variation of Fisher’s method that leads to a different alternative hypothesis . With the TPM, rejection of the null hypothesis implies that there is at least one false null hypothesis among those with p -values less than the specified tau value . Note : This method is equivalent to Fisher’s method when tau =1.

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1

Selected methods are not available in all processes.

2

Simes, R.J. (1986). An Improved Bonferroni Procedure for Multiple Tests of Significance. Biometrika 73: 751–754.

3

Zaykin, D.V., Zhivotovsky, L.A., Westfall, P.H., and Weir, B.S. (2002). Truncated Product Method for Combining p -Values. Genetic Epidemiology 22: 170–185.

To Specify a P -Value Combination Method:

Select a method from the drop-down menu.

For Additional Information

For more information about these methods, see the Methods of Smoothing p -Values in the SAS/Genetics User's Guide.