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, the appropriate hypotheses to determine if the manufacturer's claim appears reasonable are

A) H₀ : µ ?257.3 versus H₁ : µ < 257.3.
B) H₀ : µ = 250 versus H₁ : µ ? 250.
C) H₀ : µ ? 250 versus H₁ : µ > 250.
D) H₀ : µ ? 250 versus H₁ : µ < 250.