Exam 9: One-Sample Hypothesis Tests

The level of significance refers to the probability of making a Type I error.

The power of a test is the probability that the test will reject a false null hypothesis.

In the nation of Gondor,the EPA requires that half the new cars sold will meet a certain particulate emission standard a year later.A sample of 64 one-year-old cars revealed that only 24 met the particulate emission standard.The test statistic to see whether the proportion is below the requirement is

We can assume that the sample proportion is normally distributed if

In testing the hypotheses H0: π ≤ π0,H1: π > π0,we would use a right-tailed test.

If the null and alternative hypotheses are H0: μ ≤ 100 and H1: μ > 100,the test is right-tailed.

Larger samples lead to increased power,ceteris paribus.

Guidelines for the Jolly Blue Giant Health Insurance Company say that the average hospitalization for a triple hernia operation should not exceed 30 hours.A diligent auditor studied records of 16 randomly chosen triple hernia operations at Hackmore Hospital and found a mean hospital stay of 40 hours with a standard deviation of 20 hours."Aha!" she cried,"the average stay exceeds the guideline." At α = .025,the critical value for a right-tailed test of her hypothesis is

In testing a proportion,which of the following statements is incorrect?

A smaller probability of Type II error implies higher power of the test.

A sample of 16 ATM transactions shows a mean transaction time of 67 seconds with a standard deviation of 12 seconds.State the hypotheses to test whether the mean transaction time exceeds 60 seconds.

The process that produces Sonora Bars (a type of candy)is intended to produce bars with a mean weight of 56 gm.The process standard deviation is known to be 0.77 gm.A random sample of 49 candy bars yields a mean weight of 55.82 gm.Which are the hypotheses to test whether the mean is smaller than it is supposed to be?

Julia hypothesizes that fewer than 90 percent of her Visa purchases are under $100.She examines a random sample of her recent purchases and performs a test.The results shown below are from MegaStat.What would Julia conclude from this test? Explain carefully.

If we desire α = .10,then a p-value of .13 would lead us to reject the null hypothesis.

When σ is unknown,it is more conservative to use z instead of t for the critical value.

When your sample size increases,the chance of both Type I and Type II error will increase.

The probability of a false positive is decreased if we reduce α.

In a right-tailed test,a statistician got a z test statistic of 1.47.What is the p-value?

In hypothesis testing,the value of β is

Mary examined a random sample of Friday withdrawals from a college campus ATM.She hypothesized that the mean was less than $100.The results shown below are from MegaStat.What would Mary conclude from this test? Explain carefully.