Thanks Maarten & Steven, I have to change the analyses for LOS.
However, I've picked a wrong example here since I have some other
skewed variables for which KW test remains appropriate I think (eg.
triglyceride level). Can you suggest how to perform the analysis using
Stata?
Thanks in advance.
Aca
On Fri, Oct 31, 2008 at 4:24 PM, Maarten buis
<maartenbuis@yahoo.co.uk> wrote:
--- "Aca N.T." <acant29@gmail.com> wrote:
I have a simple question about testing length of stay (LOS)
differences among 5 groups. The response variable (LOS) has a skewed
distribution. I have previously transformed the LOS (log
transformation) and tried parametric statistic (ANOVA using
svy:regress), but not happy when performing back-transformation for
SD/SE. I rarely used non-parametric statistics before even for
non-survey data, so really this issue is a hassle for me. I believe,
however, that Stata has a test equivalent to Kruskal-Wallis for
survey data.
The conventional way of analysing length of stay data is using
survival
analysis. So I would -stset- the data, and than use -sts test- to do
the test. You can specify weights in the -stset- command. See:
-help stset- and -help -sts test-.
Hope this helps,
Maarten
-----------------------------------------
Maarten L. Buis
Department of Social Research Methodology
Vrije Universiteit Amsterdam
Boelelaan 1081
1081 HV Amsterdam
The Netherlands
visiting address:
Buitenveldertselaan 3 (Metropolitan), room N515
+31 20 5986715
http://home.fsw.vu.nl/m.buis/
-----------------------------------------
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