Need help with Wilcoxon rank-sum test problem!

Yoha

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Feb 25, 2012
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Hi guys,

Can anybody help with regards to this question?

Suppose we want to compare the length of hospital stay for patients with same diagnosis at two different hospitals.

First hospital: 5,8,10,13,21,26,29,32,33,44,60
Second hospital: 10,27,35,44,60,68,73,76,86,87,96,125,238

Question1: why might t-test not be very useful in this case? Book said, data is very skewed, but how I can find that myself.

Qestion 2:
Carry out non-parametric procedure for testing the length of stay are comparable in the two hospitals.

The question is answered in the back of the book and I did calculate it by software, but I would like to know how to do it manually, I tried to apply Wilcoxon sum test formula but failed to get the same numbers.
The answers: use Wilcoxon rank-sum test(large-sample test), R1=83.5, T=3.10 , p=.002
Thanks for your help!
 
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