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royk4444
Level I

What test to try for multiple comparisons (ANOVA) when variances are unequal?

Hi All,

I'm new to JMP and haven't found anything in the discussion board about my topic so I'm posting.

Basically, I want to use the Tukey-Kramer test to do pairwise mean comparisons across groups

but the variances are unequal.  I've followed up with the Welch test but it gives me just one number

when I have something like 8 groups to compare against.  Any recommendations?

RK

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Byron_JMP
Staff

Re: What test to try for multiple comparisons (ANOVA) when variances are unequal?

RK,

Take a look under the red triangle menu, at Analysis of Means Methods. There is an ANOM for variances option that will show you the variance for each group compared with the overall variance. Significant differences are outside the decision limits for each group. 

-B

http://wps.pearsoned.co.uk/wps/media/objects/10721/10978811/Ch_11/levine-smume6_topic_ANOM.pdf

JMP Systems Engineer, Pharm and BioPharm Sciences
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