The following pairs of values give X, Narco Medical’s advertising expense during a period(in hundreds of dollars), and Y, the number of the company’s sales(in thousands of dollars) for the period:

X 8 9 7 6 5 1

Y 15 11 10 11 8 5

Find the least-squares regression line using the formulas for the slope and the intercept. Also, interpret your estimates of the slope and the intercept.