An appliance manufacturer claims to have developed a compact microwave oven that consumes a mean of no more than 250 w. From previous studies, it is believed that power consumption for microwave ovens is normally distributed with a population standard deviation of 15 w. A consumer group has decided to try to discover if the claim appears true. They take a sample of 20 microwave ovens and find that they consume a mean of 257. 3 w. What are the appropriate hypotheses to determine if the manufacturer's claim appears reasonable?.