Refer to Exercise 12-9 and the regression model of time to fulfill an order based on order value.

(a) Find a 95% confidence interval for the mean time to fulfill orders that have an order value of $75,000.

(b) Find a 95% prediction interval for the time to fulfill an order for an order of value

$75,000. Interpret the difference in the intervals found in parts

(a) and (b).

(c) The leverage value for observation 8 is found to be 0.114. Would you consider this observation to have high leverage? Explain.

(d) The studentized residual for observation 17 is found to be 2.840. Using

α =0.05, what can you conclude?

(e) TheCook’sdistance forobservation17is foundtobe 0.295.What canyouconclude?