TABLE 9-3 An Appliance Manufacturer Claims to Have Developed a Compact Microwave

Multiple Choice

TABLE 9-3
An appliance manufacturer claims to have developed a compact microwave oven that consumes an average of no more than 250 W. From previous studies, it is believed that power consumption for microwave ovens is normally distributed with a 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 an average of 257.3 W.
-Referring to Table 9-3, what is the parameter of interest?

A) the mean power consumption of the 20 microwave ovens
B) the mean power consumption of all such microwave ovens
C) 250
D) 257.3