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From |
"Joseph Coveney" <jcoveney@bigplanet.com> |

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

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

Date |
Thu, 3 Dec 2009 12:06:57 +0900 |

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)? -------------------------------------------------------------------------------- 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. Joseph Coveney * * 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/

**Follow-Ups**:**st: RE: Re: Question about kwallis p-value***From:*"Nick Cox" <n.j.cox@durham.ac.uk>

**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>

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