I conduct a chi-squared analysis on some bins and conclude that an association between the bins and an event exists. I then calculate logistic regression coefficients to validate my hypothesis. Also, I always look at the observed vs expected count in each bin (from chi-squared) to guesstimate logistic regression results.
For example, if Bin 1
had an observed count = 152 but an expected count of 85, I would estimate that the over all chi-square result is likely to be significant and Bin 1 is likely to have a positive coefficient from the logistic regression. However, this Bin 1
has a negative coefficient from logistic regression. Is my understanding wrong - when observed >> expected, logistic regression coefficient should be positive?
(assuming here that results are significant).
glmfit
. $\endgroup$ – Maddy Apr 22 '14 at 21:01