Suppose the variables x
commuting distance and y
commuting time are related according to the simple linear regression model with 
10.

a. If n
5 observations are made at the x values x1
5, x2
10, x3
15, x4
20, and x5
25, calculate the standard deviations of the five corresponding residuals.

b. Repeat part

(a) for x1
5, x2
10, x3
15, x4
20, and x5
50.

c. What do the results of parts

(a) and

(b) imply about the deviation of the estimated line from the observation made at the largest sampled x value?