Practical Predictive Analytics

Fitting a GLM model

Now we will fit a logistic model using the glm package. Logistic regression typically predicts the probability of the 1 event, so make sure that the 1 events corresponds to what you want to predict. Often there is some confusion when variables are coded 1 for negative conditions such as not present, or does not exist. For our model, Pain=1 represents reduction of pain. Be sure to specify family="binomial" as an option, since that tells GLM that you will be running a logistic model:

PainGLM <- glm(Pain ~ Treatment + Gender + Age + Duration, data=df, family="binomial")  

The summary function will list the coefficients (Estimate), along with the standard error, standardized z value, and the p-values. The p-values (last column) ...