Re: st: parametric or non-parametric

[Ronan Conroy <rconroy@rcsi.ie>]

On 24 Aug 2007, at 17:37, Jen McCormick wrote:

>  My question is whether anyone has had experience analyzing Likert  
> scale data (5 point, anchored scale) using parametric methods and  
> how you transformed the data to correct for non-normal distribution.
I've used ordered logistic regression, which doesn't require  
transforming your data.

In point of fact, the big problem with your data isn't the non- 
normality of the distribution so much as the distribution of errors,  
which is binomial, and the violation of the basic assumptions of  
arithmetic: a score of 2 on a Likert scale isn't half the value of a  
score of four.



P    Before printing, think about the environment
=================================
Ronan Conroy
rconroy@rcsi.ie
Royal College of Surgeons in Ireland
120 St Stephen's Green, Dublin 2, Ireland
+353 (0)1 402 2431
+353 (0)87 799 97 95





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