TABLE 9-4
A drug company is considering marketing a new local anesthetic. The effective time of the anesthetic the drug company is currently producing has a normal distribution with an average of 7.4 minutes with a standard deviation of 1.2 minutes. The chemistry of the new anesthetic is such that the effective time should be normal with the same standard deviation, but the mean effective time may be lower. If it is lower, the drug company will market the new anesthetic; otherwise, they will continue to produce the older one. A sample of size 36 results in a sample mean of 7.1. A hypothesis test will be done to help make the decision.
-Referring to Table 9-4, the appropriate hypotheses are

Question

Quizplus · Accepted Answer

The null hypothesis (H0) should state that the mean effective time is not lower than 7.4 minutes (µ ≥ 7.4), while the alternative hypothesis (H1) should state that the mean effective time is lower than 7.4 minutes (µ < 7.4), as the company will market the new anesthetic if the mean is lower.

TABLE 9-4 A Drug Company Is Considering Marketing a New Local Anesthetic