Price and ounces. In Example 4.2 (page 154) and Exercise 4.3 (page 156) we examined the relationship between the price and the size of a Mocha Frappuccino. The 12-ounce Tall drink costs $3.50, the 16-ounce Grande is $4.00, and the 24-ounce Venti is $4.50.
(a) Plot the data and describe the relationship. (Explain why you should plot size in ounces on the x axis.)
(b) Find the least-squares regression line for predicting the price using size. Add the line to your plot.
(c) Draw a vertical line from the least-squares line to each data point. This gives a graphical picture of the residuals.
(d) Find the residuals and verify that they sum to zero.
(e) Plot the residuals versus size. Interpret this plot.