Do heavier cars really use more gasoline? Suppose a car is chosen at random. Let x be the weight of the car (in hundreds of pounds), and let y be the miles per gallon (mpg).

x	27	44	33	47	23	40	34	52
y	30	19	26	13	29	17	21	14

x = 300, y = 169, x² = 11,952, y² = 3873, xy = 5904, and r 0.9401

a) Find x, and y. Then find the equation of the least-squares line = a + bx. (Round your answers to four decimal places.)

b) Find the value of the coefficient of determination r². (Round your answer for r² to four decimal places.)

c) Suppose a car weighs x = 45 (hundred pounds). What does the least-squares line forecast for y = miles per gallon? (Round your answer to two decimal places.)