The mean heigh of American women in their twenties is about 64.3 inches, and the

Question

The mean heigh 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 of about 3.1 inches. Suppose that the correlation between the heights of husbands and wives is about r = 0.5.

(a) what are the slope and intercept of the regression line of the husband's height on the wife's height in young couples?

(b) you don't expect this prediction for single couple to be very accurate. Why not?

Explanation / Answer

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

or, y - 69.9 = 0.5*(3.1/3.9)*(x - 64.3)

or, y - 69.9 = 0.3974*(x - 64.3)

or, y - 69.9 = 0.3974x - 25.55

or, y = 0.3974x - 25.55 + 69.9 = 0.3974x + 44.35

eq. of regression line :

y = 0.3974x + 44.35 (Ans.)

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.