An automobile dealer wants to see if there is a relationship between monthly sales and the interest rate. a random sample of 4 months was taken. the results of the sample are presented below. monthly sales (y) interest rate (in percent) (x) 22 9.2 20 7.6 10 10.4 45 5.3 a) use the method of least squares to compute an estimated regression line. b) obtain a measure of how well the estimated regression line fits the data.