The mean height of American women in their twenties is about

The mean height of American women in their twenties is about 64.3 inches, and the standard deviation is about 2.8 inches. The mean height of men the same age is about 69.9 inches, with standard deviation about 2.8 inches. If the correlation between the heights of husbands and wives is about r = 0.6, what is the equation of the regression line of the husband\'s height on the wife\'s height in young couples? (Round the coefficients to at least three decimal places.)

Predict the height (± 0.1 inch) of the husband of a woman who is 67 inches tall :  

             height = _____________ inches.

Solution

y - y-bar = r(x,y)*(sd_y/sd_x)*(x - x-bar)

y-69.9=0.6 ( 2.8/2.8)(x-64.3)

y-69.9 = 0.6(x-64.3)

y=0.6x -38.58+69.9

b)

y=0.6x +31.32

y= 0.6 ( 67) +31.32

y=71.52