logistic regression: number of cases per category

Posted by student09 on Dec 23, 2010; 9:21am
URL: http://spssx-discussion.165.s1.nabble.com/logistic-regression-number-of-cases-per-category-tp3316148.html

Hello everybody,

I would be glad for advice concerning the followin problem:

The sample size for my logistic regression with four predictor variables appears somewhat small (N= 160) to me. Regarding the dichotomous dependent variable, there are 20 cases for category (a) and 140 cases for category (b). I wonder whether this might induce any problems for the results - is it ok to conduct a logistic regression with just 20 cases in one of the two categories for the dependent variable? Are there any references available regarding adeqaute sample sizes in logistic regression?  

Many thanks!
Jan