To Avoid Overfitting Data, What Should be my Rule of Thumb for the Number of Data Points per Variable?
I am currently conducting some regression analysis to predict sales, and I currently have about 45 data points and have collected a lot of potential predictor variables. However, I am weary that I will overfit the data, so I'm wondering...is there a rule of thumb as to how many variables can be assigned given a number of data points, without danger of over-fitting the data? Thanks!