In Problem 12.9 on page 490, an agent for a real estate company wanted to predict the monthly rent for one-bedroom apartments, based on the size of the apartment. The data are stored in RentSilverSpring. Use the results of that problem.
a. At the 0.05 level of significance, is there evidence of a linear relationship between the size of the apartment and the monthly rent?
b. Construct a $95 \%$ confidence interval estimate of the population slope, $\beta_1$.