The prediction equation y = 16+2s+3r+8(sr) relates y = annual income (thousands of dollars), s = sex

The prediction equation ˆy = 16+2s+3r+8(s×r)

relates y = annual income (thousands of dollars), s = sex

(s = 1 for men, s = 0 for women), and r = race (r = 1 for whites, r = 0 for blacks). By finding the four predicted means for this equation, show that the coefficient 8 of the interaction term is the amount by which the mean for one of the four groups must increase or decrease for the interaction to disappear.