topic Re: Transforming not normaly distributed data in sas in New SAS User

Transforming not normaly distributed data in sas

Aleksandar — Thu, 20 Jun 2019 09:24:45 GMT

Hello everyone,

I have not-normally distributed data and I would like to transform it for further analysis. Some data are skewed to the left and some skewed to the right. How to perform the analysis to get normally distributed data? What is the code for left and right-skewed data (log or quadratic function or something else?)?

Thank you in advance,

Aleksandar

Re: Transforming not normaly distributed data in sas

Rick_SAS — Thu, 20 Jun 2019 11:53:00 GMT

Before answering your question, can you explain WHY you want to transform the data? Most SAS procedures, including regression procedures, work just fine without requiring the data to be normally distributed.

Sometimes people think that the variables in a regression model need to be normally distributed, that is not correct. Please see the article "On the assumptions (and misconceptions) of linear regression"

Re: Transforming not normaly distributed data in sas

Aleksandar — Thu, 20 Jun 2019 13:48:36 GMT

I have checked the distribution of the variables that I am going to use as dependent variables in the model. When I checked the normality of the distribution, the p-value was lower than 1 percent for all DV-s. Therefore, I was thinking to use either afterward non-parametric tests (if I keep the data without transforming it) or to transform the data and use parametric tests. This was the main idea.

Re: Transforming not normaly distributed data in sas

Rick_SAS — Thu, 20 Jun 2019 13:55:36 GMT

Thanks. None of that is necessary. DVs do not need to be normally distributed. (Neither do the IVs.) Please read that article I linked to.

Re: Transforming not normaly distributed data in sas

Aleksandar — Thu, 20 Jun 2019 14:18:18 GMT

I will read the article to gain more knowledge. Thank you very much for comments.