The mean height of American women in their twenties is about 64 inches, and the standard deviation is about 2.7 inches. The mean
height of men the same age is about 69.3 inches, with standard deviation about 2.8 inches. If the correlation between the heights of husbands and wives is about r = 0.5, what is the slope of the regression line used to predict the husband's height (Y) from the wife's height (X) in young couples?