Exam 9: Hypothesis Tests

For a two-tailed hypothesis test about μ, we can use any of the following approaches EXCEPT compare the _____ to the _____.

When the rejection region is in the lower tail of the sampling distribution, the p-value is the area under the curve _____.

The level of significance is the _____.

The error of rejecting a true null hypothesis is _____.

The average life expectancy of tires produced by Whitney Tire Company has been 40,000 miles. Management believes that due to a new production process, the life expectancy of its tires has increased. In order to test the validity of this belief, the correct set of hypotheses is _____.

Read the z statistics from the normal distribution table and circle the correct answer. A two-tailed test at a .0694 level of significance; z = _____.

A manufacturer claims that at least 40% of its customers use coupons. A study of 25 customers is undertaken to test that claim. The results of the study follow: yes no no yes y es no yes no no yes no no no no yes no no no no yes no no yes no yes At a .05 level of significance, use Excel to test the manufacturer's claim.

Read the z statistic from the normal distribution table and circle the correct answer. A one-tailed test (lower tail) at a .063 level of significance; z = _____.

A two-tailed test is performed at a 5% level of significance. The p-value is determined to be .09. The null hypothesis _____.

At a local university, a sample of 49 evening students was selected in order to determine whether the average age of the evening students is significantly different from 21. The average age of the students in the sample was 23 years. The population standard deviation is known to be 3.5 years. Determine whether or not the average age of the evening students is significantly different from 21. Use a .1 level of significance.

A national poll reported that 58% of those with Internet access have made purchases online. To investigate whether this percentage applies to its own state, a legislator commissions a study. A random sample of 400 state residents who have Internet access is taken. Of those 400 respondents, 215 said that they have made purchases online. Does this sample provide sufficient evidence to conclude that the state differs from the nation with respect to making purchases online? Use the p-value to conduct the hypothesis test and use a .05 level of significance.

Which Excel function would NOT be appropriate to use when conducting a hypothesis test for a population proportion?

In hypothesis testing, the critical value is _____.

Excel's __________ function can be used to calculate a p-value for a hypothesis test when σ is unknown.

For a two-tailed hypothesis test with a test statistic value of z = 2.05, the p-value is _____.

In a television commercial, the manufacturer of a toothpaste claims that at least four out of five dentists recommend its product. A consumer-protection group wants to test that claim. Identify the hypotheses.

In order to test the hypotheses H₀: μ ≤ 100 and H_a: μ > 100 at an α level of significance, the null hypothesis will be rejected if the test statistic z is _____.

A lathe is set to cut bars of steel into lengths of 6 cm. The lathe is considered to be in perfect adjustment if the average length of the bars it cuts is 6 cm. A sample of 121 bars is selected randomly and measured. It is determined that the average length of the bars in the sample is 6.08 cm. The population standard deviation is 0.44 cm. Determine whether or not the lathe is in perfect adjustment. Use a .05 level of significance.

If the cost of a Type I error is high, a smaller value should be chosen for the _____.

Read the t statistic from the table of t distributions and circle the correct answer. A two-tailed test, a sample of 20 at a .20 level of significance; t = _____.