On the Programming Examples menu above, you will find example programs that show how to do the same tasks in R, SAS, SPSS and Stata. They use simple practice data sets that are easy to understand and work with. If you run the code and see the result, it is usually clear how each package performs each task. The R programs in particular go through additional steps to show variations on the solution. The examples are explained step-by-step in my books R for SAS and SPSS Users and R for Stata Users. Both the example programs and their data sets are also available under Downloads.