Table 3.9 on page 53 showed data for several nations on y = C02 emissions (in metric tons per capita) and x =

per capitaGDP(in thousands of dollars). Let z =whether the nation is in Europe (1 = yes, 0 = no).

(a) The prediction equation for the effect of z is ˆy =

10.61 − 2.48z. Interpret the coefficients.

(b) The prediction equation for the effects of x and z is

ˆy = 2.10 + 0.22x − 3.58z. Interpret the coefficients.