Practice test 3

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Unformatted text preview: Bus Stat Test 3 Practice Test Multiple Choice Identify the choice that best completes the statement or answers the question. ____ 1. The level of significance a. can be any positive value b. can be any value c. is (1 - confidence level) d. can be any value between -1.96 to 1.96 ____ 2. The average life expectancy of tires produced by the Whitney Tire Company has been 40,000 miles. Management believes that due to a new production process, the life expectancy of their tires has increased. In order to test the validity of their belief, the correct set of hypotheses is a. H : μ < 40,000 H a : μ 40,000 b. H : μ 40,000 H a : μ > 40,000 c. H : μ > 40,000 H a : μ 40,000 d. H : μ 40,000 H a : μ < 40,000 Exhibit 9-1 n = 36 = 24.6 S = 12 H : μ 20 H a : μ > 20 ____ 3. Refer to Exhibit 9-1. If the test is done at 95% confidence, the null hypothesis should a. not be rejected b. be rejected c. Not enough information is given to answer this question. d. None of these alternatives is correct. Exhibit 9-3 n = 49 = 54.8 s = 28 H : μ = 50 H a : μ 50 ____ 4. Refer to Exhibit 9-3. The p-value is equal to a. 0.1151 b. 0.3849 c. 0.2698 d. 0.2302 ____ 5. Refer to Exhibit 9-3. If the test is done at the 5% level of significance, the null hypothesis should a. not be rejected b. be rejected c. Not enough information given to answer this question. d. None of these alternatives is correct. 1 Exhibit 9-4 The manager of a grocery store has taken a random sample of 100 customers. The average length of time it took the customers in the sample to check out was 3.1 minutes with a standard deviation of 0.5 minutes. We want to test to determine whether or not the mean waiting time of all customers is significantly more than 3 minutes. ____ 6. Refer to Exhibit 9-4. The standardized test statistic is a. 1.96 b. 1.64 c. 2.00 d. 0.056 ____ 7. For a two-tailed test at 86.12% confidence, Z = a. 1.96 b. 1.48 c. 1.09 d. 0.86 ____ 8. For a one-tailed test (upper tail), a sample size of 18 at 95% confidence, t = a. 2.12 b.-2.12 c.-1.740 d. 1.740 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 different from 24. Assume the distribution of the population of ages is normal. ____ 9. Refer to Exhibit 9-6. At 95% confidence, it can be concluded that the mean age is a. not significantly different from 24 b. significantly different from 24 c. significantly less than 24 d. significantly less than 25 ____ 10. For a one-tailed test (lower tail) at 89.8% confidence, Z = a.-1.27 b.-1.53 c.-1.96 d.-1.64 ____ 11. For a one-tailed test (upper tail), a sample size of 26 at 90% confidence, t = a. 1.316 b.-1.316 c.-1.740 d. 1.740 ____ 12. For a one-tailed test (lower tail), a sample size of 22 at 95% confidence, t = a.-1.383 b. 1.383 c.-1.717 d.-1.721 2 ____ 13. Which of the following statements is ...
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