I have dataset at my disposal and I am suppose to run a logistic regression. What is the best way to determine which explanatory variables are useful and which are totally off? Is there any general rule or procedure to help me? Could you please share some guide for this? Is there any graphical way to determine this?
Thanks for help.
EDIT: I am looking for general and user-friendly way to do this, like some indications in plot of 2 variables. I am not looking for "technical" solution.