Table 1-4 on the book's website gives monthly data on the closing prices of the Dow Jones Industrial Average and the Standard & Poor's 500 stock market indexes. The data are from Yahoo Finance's historical stock quotations page.

a. Plot these data with time on the horizontal axis and the two variables on the vertical axis. If you prefer, you may use a separate figure for each variable.

b. What relationships do you expect to find between the two indexes? Why?

c. For each variable, “eyeball” a regression line from the scattergram.