sample size calculation for Chi-squared test

[froji]

Hi,

My data has a categorical independent variable (3 groups) and a dicohotomous (yes/no) dependent variable. I was planning to use a Chi-squared test to see if there is a difference between the groups. However I first need to calculate the sample size, since I didn't find a way to do this in SPSS I am trying to do this in SAS studio.

Is this the correct test to use for my data types or are there better tests to do it? How do I calculate the sample size if the alfa is 0.05, the power is 0.80 and I have a 3X2 tabel as described above?

[StatDave]

You can do this either with the POWERRxC macro or with PROC POWER. Both are illustrated for a 4x2 table in Example 3 in the Results tab in the POWERRxC macro documentation.