Cigarette smoking. The data in Table 7 shows that the percentage of female cigarette...

Cigarette smoking. The data in Table 7 shows that the percentage of female cigarette smokers in the U.S. declined from 22.1% in 1997 to 18.0% in 2006.

(A) Applying linear regression to the data for females in Table 7 produces the model

f = -0.47t + 22.19

where f is percentage of female smokers and t is time in years since 1997. Draw a scatter plot of the female smoker data and a graph of the regression model on the same axes for 0 ≤ t ≤30.

(B) Estimate the first year in which the percentage of female smokers is less than 10%.