Re: is it correct if I use Mann-Whitney U?

Posted by Marta García-Granero on Jan 22, 2007; 4:55pm
URL: http://spssx-discussion.165.s1.nabble.com/is-it-correct-if-I-use-Mann-Whitney-U-tp1073199p1073203.html

Hi Simon

SSP> There are simple extensions of McNemar's test from a dichotomous outcome
SSP> variable to a polytomous variable such as yours. These extensions,
SSP> unfortunately, are not available in SPSS.

If I remember correctly, SPSS exact tests module includes marginal
homogeneity test, one of the extensions of McNemar test you are
talking about...

Omar, do you have that module (EXACT TESTS) installed in your
computer?

SSP> Also, while a before and after
SSP> design is one example where you might use McNemar's test, any situation
SSP> with paired data could be used.

I'd try Wicoxon test, although I agree that there'll be a lot of tied
data. If sample size is over 25, the asymptotic p-value will be OK and
since it is corrected for ties, there shouldn't be an important loss
of power.


--
Regards,
Dr. Marta García-Granero,PhD           mailto:[hidden email]
Statistician