1. One of the earliest uses of the correlation coefficient was by Sir Francis Galton, who computed the corre- lation between height and forearm length for a sam- ple of adult men. Assume that the least-squares line for predicting forearm length (y) from height (x) is y = -0.2967 + 0.2738x . Both forearm length and height are measured in inches in this equation.
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 con- clude that all their forearms will be at least 19 in. long? Explain.