Exam 9: Introduction to Hypothesis Testing

A sample is used to obtain a 95 percent confidence interval for the mean of a population.The confidence interval goes from 15 to 19.If the same sample had been used to test the null hypothesis that the mean of the population is equal to 20 versus the alternative hypothesis that the mean of the population differs from 20,the null hypothesis could be rejected at a level of significance of 0.05.

When using the t-distribution in a hypothesis test,the population does not need to be assumed normally distributed.

In conducting a hypothesis test where the conclusion is to reject the null hypothesis,then either a correct decision has been made or else a Type I error.

When testing a two-tailed hypothesis using a significance level of 0.05,a sample size of n = 16,and with the population standard deviation unknown,which of the following is true?

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.

A report recently submitted to the managing partner for a market research company stated "the hypothesis test may have resulted in either a Type I or a Type II error.We won't know which one occurred until later." This statement is one that we might correctly make for any hypothesis that we have conducted.

Woof Chow Dog Food Company believes that it has a market share of 25 percent.It surveys n = 100 dog owners and ask whether or not Woof Chow is their regular brand of dog food,and 23 people say yes.Based upon this information,what is the critical value if the hypothesis is to be tested at the 0.05 level of significance?

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.

Which of the following is not a required step in finding beta?