When analyzing a linear regression model built for the purpose of understanding an important problem (and not for predicting), which of the following must be considered? Check all the correct answers.

Group of answer choices

Determine if there is any multicollinearity and reduce it.

Identify and analyze not only variables that are included in the model but also those variables that are left out.

Evaluate the significance of the variables as well as that of the whole model.

Analyze both the model statistics as well as the signal-to-noise ratios of individual variables.