Exam 9: Introduction to Hypothesis Testing

A city newspaper has stated that the average time required to sell a used car advertised in the paper is less than 5 days.Assuming that the population standard deviation is 2.1 days,if the "true" population mean is 4.1 days and a sample size of n = 49 is used with an alpha equal to 0.05,the probability that the hypothesis test will lead to a Type II error is approximately .0869.

In testing a hypothesis,statements for the null and alternative hypotheses as well as the selection of the level of significance should precede the collection and examination of the data.

A recent report in which a major pharmaceutical company released the results of testing that had been done on the cholesterol reduction that people could expect if they use the company's new drug indicated that the Type II error probability for a given "true" mean was 0.1250 based on the sample size of n = 64 subjects.Given this,what was the power of the test under these same conditions? The alpha level used in the test was 0.05.