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

x 29 43 29 47 23 40 34 52

y 29 20 26 13 29 17 21 14

Complete parts (a) through (e), givenx=297,y=169,x²=11,729,y²=3853,xy=5855,andr0.940.

(c) Findx, andy. Then find the equation of the least-squares line=a+bx. (Round your answers forxandyto two decimal places. Round your answers foraandbto three decimal places.)

x=_______

y=____________

y^=____+__________x

(d) Graph the least-squares line. Be sure to plot the point (x,y) as a point on the line.

(e) Find the value of the coefficient of determinationr². What percentage of the variation inycan beexplainedby the corresponding variation inxand the least-squares line? What percentage isunexplained? (Round your answer forr²to three decimal places. Round your answers for the percentages to one decimal place.)

r²=_________

explained _____%

unexplained____%

(f) Suppose a car weighsx=32(hundred pounds). What does the least-squares line forecast fory= miles per gallon? (Round your answer to two decimal places.)

___________mpg