A critically important aspect of customer service at a supermarket is the waiting time at the checkout. Refer to the data file Supermarket, which contains total number of customers in the store (x) and the waiting times (y) during time periods where there were a constant number of checkout counters open. The linear regression equation is given below.

yn i = -0.4142 + 0.1274xi

a. Interpret the coefficient b1 = 0.1274 for the supermarket.

b. What will the waiting time be on average when there are 23 customers?

c. Suppose you were asked to estimate the waiting time if only six customers are in the store. Discuss your response to this request.