9/15/2023
Section 4.1 - see GoogleDrive\Stat216-Nonparametrics-F2023\!Class Notes\Section4.1-Notes-BH.pdf
Two Sample Location Problem
Models for location alternatives
Wilcoxon Rank Sum Test
The null distribution of the Wilcoxon rank sum statistic
Class Exercise - Find the null distribution of W when we have m=3 X observations and n=2 Y observations.
Ties Corrections
The W* LSA test in the case of ties is conservative if we do not use the correction. i.e., If we reject the null hypothesis without the correction, then we would also reject the null hypothesis with it.
General recommendation:
- Compute W* without the ties correction
- Find the p-value for this uncorrected W*. If the p-value is less than or equal to alpha, reject the null hypothesis and do not mess with the ties correction.
- If the p-value is greater than alpha, but close to alpha, then use the ties correction and recompute alpha.
- If the p-value is greater than alpha, but not close to alpha, ignore the ties correction.
We will have a problem session and lab on Monday. Please complete your reading of Chapter 4 for class on Wednesday.