title: LLR p-value is nan during logistic regression using statsmodel in python
body: <p>I use the python library statsmodel to do logistic regression and the the following results I got a log-likelihood -27 and LL-Null the same, but p value nan, where it supposed to be 1. I wonder what's the cause of NaN and how can I recover it to a real number. I tried to use Decimal to increase precision but it does not work with statsmodel's fit. I also tried to read logit code but did not find it.</p>