In Galton's height data (Figure 7.1, in Section 7.1), the least-squares line for predicting forearm length (y) from height (x) is y = −0.2967 + 0.2738x.
a. Predict the forearm length of a man whose height is 70 in.
b. How tall must a man be so that we would predict his forearm length to be 19 in.?
c. All the men in a certain group have heights greater than the height computed in part (b). Can you conclude that all their forearms will be at least 19 in. long? Explain.