Problem: Husbands and wives. The mean height of American women in their twenties is about 64.3 inches, and the standard deviation is about 3.9 inches. The mean height of men the same age is about 69.9 inches, with standard deviation about 3.1 inches. Suppose that the correlation between the heights of husbands and wives is about r 0.5.
Required:
(i) What are the slope and intercept of the regression line of the husband's height on the wife's height in young couples?
(ii) Draw a graph of this regression line for heights of wives between 56 and 72 inches. Predict the height of the husband of a woman who is 67 inches tall, and plot the wife's height and predicted husband's height on your graph.
(iii) You don't expect this prediction for a single couple to be very accurate. Why not?