A report on the average price of a sample of brand- name prescription drugs with their generic equivalents has found the generics to be considerably cheaper. The drugs and the average prices for their brand-name versus generic versions are listed in data file XR03047. Generate a scatter diagram with axes of your choice, fit a linear equation to the data, then determine and interpret the coefficients of correlation and determination. Source: Julie Appleby, "Drug Makers Fight Back As Patents Near Expiration," USA Today, November 26, 1999, p. 4B.
Note: For many of the Exercises 3.48-3.64, a computer and statistical software will be desirable and useful.
However, any necessary calculations can also be done with the aid of a pocket calculator. For readers using statistical software, keep in mind the file-naming key- for example, the data for Exercise 3.57 will be in data file XR03057.