Exam 9: Hypothesis Tests

Consider the following hypothesis test: Ho: μ ≥ 14 Ha: μ < 14 A sample of 64 provides a sample mean of 13 and a sample standard deviation of 4. a. Determine the standard error of the mean. b. Compute the value of the test statistic. c. Determine the p-value; and at 95% confidence, test the above hypotheses.

The Bureau of Labor Statistics reported that the average yearly income of dentists in the year 2009 was $110,000. A sample of 81 dentists, which was taken in 2010, showed an average yearly income of $120,000. Assume the standard deviation of the population of dentists in 2010 is $36,000. a. We want to test to determine if there has been a significant increase in the average yearly income of dentists. Provide the null and the alternative hypotheses. b. Compute the test statistic. c. Determine the p-value; and at 95% confidence, test the hypotheses.

Exhibit 9-7 A random sample of 16 statistics examinations from a large population was taken. The average score in the sample was 78.6 with a variance of 64. We are interested in determining whether the average grade of the population is significantly more than 75. Assume the distribution of the population of grades is normal. -Refer to Exhibit 9-7. At 95% confidence, it can be concluded that the average grade of the population

Read the Z statistic from the normal distribution table and circle the correct answer. A one-tailed test upper tail) at 87.7% confidence; Z =

If a hypothesis test leads to the rejection of the null hypothesis,

For a one-tailed test upper tail) at 93.7% confidence, Z =

For a one-tailed hypothesis test upper tail) the p-value is computed to be 0.034. If the test is being conducted at 95% confidence, the null hypothesis

A two-tailed test is performed at 95% confidence. The p-value is determined to be 0.09. The null hypothesis

In order to test the following hypotheses at an α level of significance H0: μ ≤ 800 Ha: μ > 800 The null hypothesis will be rejected if the test statistic Z is

Consider the following hypothesis test: Ho: P ≤ 0.8 Ha: P > 0.8 A sample of 400 provided a sample proportion of 0.853. a. Determine the standard error of the proportion. b. Compute the value of the test statistic. c. Determine the p-value; and at 95% confidence, test the above hypotheses.

A Type II error is committed when

For a one-tailed test lower tail), a sample size of 10 at 90% confidence, t =

If the probability of a Type I error α) is 0.05, then the probability of a Type II error β) must be

Exhibit 9-6 A random sample of 16 students selected from the student body of a large university had an average age of 25 years and a standard deviation of 2 years. We want to determine if the average age of all the students at the university is significantly more than 24. Assume the distribution of the population of ages is normal. -Refer to Exhibit 9-6. The test statistic is

A weatherman stated that the average temperature during July in Chattanooga is 80 degrees or less. A sample of 32 Julys is taken. The correct set of hypotheses is

If a hypothesis is rejected at 95% confidence, it

Exhibit 9-2 n = 64 = 50 s = 16 H0: μ ≥ 54 Ha: μ < 54 -Refer to Exhibit 9-2. The p-value is between

In a two-tailed hypothesis test the test statistic is determined to be Z = -2.5. The p-value for this test is

For a lower bounds one-tailed test, the test statistic z is determined to be zero. The p-value for this test is

The probability of committing a Type I error when the null hypothesis is true is