Explanation of proc npar1way output for Wilcoxon Sum Rank Statistic (std dev under Ho etc)

MaryA_Marion — Mon, 18 Oct 2021 13:45:32 GMT

I need to know how the following statistics are calculated: std dev under Ho, Mean Score and t approximation.

See code below. Does SAS test for size of samples and use approximation when appropriate? I question the output.

data one;
input sample resp;
1 1
1 3
1 2
1 3
1 5
2 4
2 7
2 6
2 8
2 6
;
proc NPAR1WAY data=one wilcoxon;
        title "Nonparametric test to compare medians";
        class sample;
        var resp;
        exact wilcoxon;
   run;

Re: Explanation of proc npar1way output for Wilcoxon Sum Rank Statistic (std dev under Ho etc)

Rick_SAS — Mon, 18 Oct 2021 14:16:31 GMT

Since your example has tied values, please read how PROC NPAR1WAY treats tied values. That is a common source of error for people who are trying to reproduce the output.

The documentation includes

The formulas for the scores and statistics
The modifications for exact tests

topic Explanation of proc npar1way output for Wilcoxon Sum Rank Statistic (std dev under Ho etc) in Statistical Procedures

Explanation of proc npar1way output for Wilcoxon Sum Rank Statistic (std dev under Ho etc)

Re: Explanation of proc npar1way output for Wilcoxon Sum Rank Statistic (std dev under Ho etc)