Refer to Exercise 11.55.
(a) Calculate the sample correlation coefficient.
(b) What proportion of the y variability is explained by the fitted regression line?
Exercise 11.55
A recent graduate moving to a new job collected a sample of monthly rent (dollars) and size (square feet) of 2-bedroom apartments in one area of a midwest city.

(a) Plot the scatter diagram and find the least squares fit of a straight line.
(b) Do these data substantiate the claim that the monthly rent increases with the size of the apartment? (Test with a = .05).
(c) Give a 95% confidence interval for the expected increase in rent for one additional square foot.
(d) Give a 95% prediction interval for the monthly rent of a specific apartment having 1025 square feet.

Size Rent Size Rent 0771075 1288 1270 842 760 1210 1175 1204 1125 945 84s 1192 1035 820 885