topic Re: Fisher's Exact Test zero sum row warning in SAS Procedures

Fisher's Exact Test zero sum row warning

mgrovesteen — Wed, 01 Nov 2017 20:02:44 GMT

I tried to obtain a p-value for a 2 x 2 contingency table in which one row sums to zero. I used PROC FREQ along with the exact fisher option. The following warning was generated: "Row or column sum zero. No statistics computed for this table." For a Fisher's Exact test, the p-value should be calculated as 1 here. Can anyone tell me why SAS won't produce results when it can be calculated? (I am able to get results for other contingency tables without zero sum rows, so my code is correct.)

Re: Fisher's Exact Test zero sum row warning

Reeza — Wed, 01 Nov 2017 20:45:42 GMT

0 rows are problematic for sure, especially if the row wouldn't even appear in the data set. It means a p-value cannot be calculated, what makes you think the p-value should be 1?

Re: Fisher's Exact Test zero sum row warning

ballardw — Wed, 01 Nov 2017 22:40:18 GMT

Find a book on statistics that shows how to manually calculate a chi-square test statistic for a 2x2 table.

Do it with some tables that have a row total count of 0.

Then try to find that test statistic in a Chi-square table.