An industrial engineer is evaluating workflow in an online retail fulfillment center. Online fulfillment involves three tasks which must be performed in the following sequence: [1] pick the merchandise from inventory, [2] pack the merchandise in boxes, [3] ship the packed boxes. The amount of time it takes to complete each task is normally distributed with parameters given in the table below. Assume that the time it takes to complete each task is independent of the other tasks).

d. For the same sample of 15 orders, what is the probability that the sample mean for the entire process is less than 120 seconds (two minutes)? Hint: the entire process requires completion of each task one after the other in the sequence shown. e. By automating the ship task, the mean and standard deviation of this task's time would be cut in half, so the mean () = 10 seconds. If workers are paid $27/hour, or $.0075/second, how much would the online retailer expect to save on labor for its 750,000 annual orders by automating?