General question on linear models

Module 4. Linear Models
#1

In module 4, the general process of splitting the data into training and test, and then running some cross-validation procedure, is not present anymore. The goal is still to building predictive models. Any reason why it is so?

Thanks.

#2

Actually I am just starting the Exercise M4.03, and there is indeed cross-validation.

#3

The reason was to get intuition in the linear model and the fitting process and not really carrying about the prediction. However, as you mentioned, when we ask to use the model in a prediction setting then we will use again the cross-validation.