A roadrunner is a desert bird that tends to run instead of fly. While running, the roadrunner uses its tail as a balance. A sample of 10 roadrunners was taken, and the birds’ total length, in centimeters (cm), and tail length, in cm, were recorded. The output shown in the table is from a least-squares regression to predict tail length given total length. Suppose a roadrunner has a total length of 59.0 cm and tail length of 31.1 cm. Based on the residual, does the regression model overestimate or underestimate the tail length of the roadrunner?
answer choices
a. Underestimate, because the residual is positive.
b. Underestimate, because the residual is negative.
c. Overestimate, because the residual is positive.
d. Overestimate, because the residual is negative.
e. Neither, because the residual is 0.