1. A hardware store chain has just received a truck- load of 5000 electric drills. Before accepting the shipment, the purchasing manager insists that 9 of the drills be randomly selected for testing. He intends to measure the maximum power consumption of each drill and reject the shipment if the mean consumption for the sample is greater than the 300 watts listed on the product label. Unknown to the purchasing manager, the drills on the truck require an average of 295 watts, with a standard deviation of 12 watts. Stating any additional assumptions you are using, find the probability that the truckload of drills will be rejected.

2. The tensile strength of spot welds produced by a robot welder is normally distributed, with a mean of 10,000 pounds per square inch and a standard deviation of 800 pounds per square inch. For a simple random sample of n 5 4 welds, what is the probability that the sample mean will be at least 10,200 pounds per square inch? Less than 9900 pounds per square inch?