To determine how the number of housing starts is affected by mortgage rates, an economist recorded the average mortgage rate and the number of housing starts in a large country for the past 10 years. These data are listed here.
Rate 8.5 7.8 7.6 7.5 8.0 8.4 8.8 8.9 8.5 9.0
Starts 115 111 185 201 206 167 155 117 133 150
(a) Determine the regression line.
(b) What do the coefficients of the regression line tell you about the relationship between mortgage rates and housing starts?