In this video, I explain how to code categorical variables for use as explanatory variables (x-variables) in regression by using indicator or dummy variables. Categorical variables are very common in real data sets, so understanding how to create and use dummy variables is both very useful and important.

A pdf copy of the slides that are used in the video can be found here. The video also discusses an example which is implemented in Excel. The Excel file can be downloaded here.

This video discusses the bias vs. variance tradeoff, overfitting, and basic cross validation. There are two parts. Part 1 (below) discusses the ideas. Part 2 shows an example using regression trees.

A pdf file of the slides used in this video can be obtained here.