Hi!

 

I'm comparing the differences in contaminant concentration between 2
different groups of people ( N=36, N=37). When using a simple linear
regression model I found no differences between groups, but when evaluating
the diagnostic plots of the residuals I found my independent variable to
have deviations from normality (even after log transformation). Therefore I
have used bootstrap on the regression parameters ( R= 1000 & R=10000) and
this confirms my results , i.e., no differences between groups ( and the
distribution is log-normal). However, when using wilcoxons' rank sum test on
the same data set I find differences between groups. 

 

Should I trust the results from bootstrapping or from wilcoxons' test?

 

Thanks!

 

Regards

 

Lotta Rylander


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