topic Re: Statistical Test when cross table has less than 5 cases for majority of the cells in Statistical Procedures

Statistical Test when cross table has less than 5 cases for majority of the cells

Shivi82 — Sun, 26 Jun 2016 18:03:37 GMT

Dear Team,

i am working on a survey data and need to run a chi square test to see if there is any relation between gender and rating.

As one of the assumption of Chi Square is : Sample Size: each particular scenario (cell) must have at least five cases. However as i have very less data points hence this assumption is violated.

We can run a fisher exact test in this scenario though while researching i came across a literature from "Wai Wan Tsang and Kai Ho Cheng" from the Univeristy of The University of Hong Kong" that we can still run a chi square test.

I am a bit confused and while searching this on researchgate. net this option was suggested hence checking on the forum if this is still a valid test to conduct.

Regards, Shivi

Re: Statistical Test when cross table has less than 5 cases for majority of the cells

PGStats — Sun, 26 Jun 2016 18:15:34 GMT

You can request exact statistics for the likelihood ratio chi-square test (if that what your reference is about) with EXACT LRCHI;

Re: Statistical Test when cross table has less than 5 cases for majority of the cells

Rick_SAS — Sun, 26 Jun 2016 19:11:08 GMT

Yes, it sounds like exact tests would be appropriate. For an overview of exact tests in PROC FREQ, see "Exact tests in PROC FREQ: What, when, and how."

If you have many dozens of cells, a full exact test might be prohibitively expensive. In that case, you can use Monte Carlo approximations to the exact test by adding the MC option to the EXACT statement:

exact pchi / MC;     /* Monte Carlo approximation to exact chi-square test */

Re: Statistical Test when cross table has less than 5 cases for majority of the cells

Shivi82 — Mon, 27 Jun 2016 14:04:32 GMT

Thanks Rick for the solution. I think this works perfect. Also thanks for sharing the blog link.