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From |
"Nick Cox" <n.j.cox@durham.ac.uk> |

To |
<statalist@hsphsun2.harvard.edu> |

Subject |
st: RE: Re: Question about kwallis p-value |

Date |
Thu, 3 Dec 2009 12:16:46 -0000 |

Although Joseph as always gives good advice, it is also arguable that if a structure of groups and of individuals within groups is key, then any test like this is misdirected. It is difficult to advise without knowing much more about the data. Nick n.j.cox@durham.ac.uk Joseph Coveney If you have ties in your response variable, then you'd be better off using the with-ties p-value. You can check for ties with the Stata command -isid-. sysuse census kwallis medage, by(region) isid medage If you're interested in within-person comparisons, then there's Friedman's test; there are user-written commands, e.g., -friedman- and -skilmack-. For between-groups testing where there are multiple observations on each person, there is van Elteren's test (two groups at a time), again, with a user-written command, -vanelteren-. Another user-written command that could be helpful in your case is -somersd-, which allows for a -cluster()- option. All of these can be downloaded from SSC (-help ssc- for how). You can try -permute- with a randomized-block ANOVA, too. As I recall, there's a worked example in the documentation for -permute-, which is an official Stata command. "a statistical test for medians"--many nonparametric tests are tests of location only when the scale is the same between groups. Mahboobeh Safaeian wrote: I am using the Kruskal Wallis rank test to see if there are any statistically significant differences in 3 different groups. I have 2 questions (unrelated): 1) How do I determine whether I use the p-values with ties or without ties? 2) is there a statistical test for medians that can account for multiple observations per person (kind of like a GEE)? * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**References**:**Re: st: Plotting a Local Polynomial Regression with CIs Accounting for Clustering***From:*Maarten buis <maartenbuis@yahoo.co.uk>

**Re: st: Plotting a Local Polynomial Regression with CIs Accounting for Clustering***From:*Austin Nichols <austinnichols@gmail.com>

**Re: st: Plotting a Local Polynomial Regression with CIs Accounting for Clustering***From:*L S <lts40301@gmail.com>

**st: Question about kwallis p-value***From:*"Safaeian, Mahboobeh (NIH/NCI) [E]" <safaeianm@mail.nih.gov>

**st: Re: Question about kwallis p-value***From:*"Joseph Coveney" <jcoveney@bigplanet.com>

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