R help - Sep 2010 - Power analysis

I am aware this is fairly simple, but is currently driving me mad! Could
someone help me out with conducting a post-hoc power analysis on a Wilcoxon
test. I am being driven slightly mad by some conflicting advice!
Thanks in advance,

Lewis

	[[alternative HTML version deleted]]

Be happy, don't do post-hoc power analyses.

The standard "post-hoc power analysis" is actually counterproductive.
It is much better to just create confidence intervals.  Or give a better
description/justification showing that your case is not the standard/worse than
useless version.

-- 
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at imail.org
801.408.8111

> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of Lewis G. Dean
> Sent: Thursday, September 02, 2010 9:45 AM
> To: r-help at r-project.org
> Subject: [R] Power analysis
> 
> I am aware this is fairly simple, but is currently driving me mad!
> Could
> someone help me out with conducting a post-hoc power analysis on a
> Wilcoxon
> test. I am being driven slightly mad by some conflicting advice!
> Thanks in advance,
> 
> Lewis
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-
> guide.html
> and provide commented, minimal, self-contained, reproducible code.

Agree with Greg's point. In fact it does not make logical sense in many
cases. Similar to the use of the "statistically unreliable"
reliability
measure Cronbach's alpha in some non-statistical fields.
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Lewis G. Dean wrote:
> 
>> post-hoc power analysis on a Wilcoxon test. 
> 
There is a (somewhat dated) list of "why-not" papers in

http://www.childrens-mercy.org/stats/size/posthoc.asp

Dieter



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