A lightbulb manufacturer wants to know the number of defective bulbs contained in a typical box shipped by the company. Production personnel at this company have recorded the number of defective bulbs found in each of the 1000 boxes shipped during the past week. These data are provided in P8_11.XLS. Using this shipment of boxes as a frame, select a simple random sample of 50 boxes and compute the mean number of defective bulbs found in a box.