example_mww

# example_mww - Stat 2225 Handout Example of Wilcoxon...

This preview shows pages 1–2. Sign up to view the full content.

Stat 2225 Handout Example of Wilcoxon Rank-Sum Test Q17.7 on p.569. Sample #1 60 66 73 75 81 Rank #1 1 2 4 5 7 Sample #2 72 78 82 90 103 Rank #2 3 6 8 9 10 H 0 : the two population locations are the same H a : the location of population 1 is to the left of the location of population 2 T 1 = 19 and T 2 = 36, n 1 = n 2 = 5; T = T 1 = 19. Based on α = 0.05, T L = 19 and T U = 36. The rejection region is therefore either T 19. Test statistic is 19 and is equal to T L . Therefore, we have enough evidence to reject H0. SGP Output: Comparison of Medians --------------------- Median of sample 1: 73.0 Median of sample 2: 83.0 Mann-Whitney (Wilcoxon) W test to compare medians Null hypothesis: median1 = median2 Alt. hypothesis: median1 < median2 Average rank of sample 1: 3.8 Average rank of sample 2: 7.2 W = 21.0 P-value = 0.0473463 Note: Make sure you know how to find the test statistic of “21” from the output. Q17.17 on p.570. Type 0: the histogram shows that it’s not reasonable to believe that the populations are from normal distribution Æ use non-parametric test.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

## This note was uploaded on 01/17/2010 for the course STATS 2225 taught by Professor Li during the Spring '09 term at Langara.

### Page1 / 2

example_mww - Stat 2225 Handout Example of Wilcoxon...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online