12.10 Simple Linear Regression: Always Plot Your Data!

A quick look at a few cautions about simple linear regression. Anscombe’s quartet can be found in: Anscombe, F. (1973). Graphs in statistical analysis. American Statistician, 27:17–21. The fuel use vs speed data is found in: West, B.H., McGill,R.N., Hodgson, J.W., Sluder, S.S. , and Smith D.E., Development and Verification of Light-Duty Modal Emissions and … Read more

12.11 Simple Linear Regression: Transformations

A look at transformations in the context of simple linear regression. I look at two examples where taking a transformation (applying a function to the response and/or explanatory variables) can help to satisfy the assumptions of the simple linear regression model. The brain and body weight data is from: Sacher, G.A. Staffeldt, E. (1974). Relation … Read more

12.14 The Pooled-Variance t Test as a Regression

A look at the relationship between the pooled-variance t test and simple linear regression. I illustrate how the pooled-variance t test can be done as a regression, by declaring an appropriate indicator variable. The Cairo traffic police officer data is simulated data with the same summary statistics as found in: Kamal, A., Eldamaty, S., and … Read more