MATH 3339 Test 2 Spring 2019

Question 7 Your answer is CORRECT. A sample of 30 boxes of cereal has a sample standard deviation of 0.81 ounces. Construct a 93% confidence interval to estimate the true standard deviation of the filling process for the boxes of cereal. a) (0.656, 1.064) b) (0.520, 1.100) c) (0.430, 1.132) d) (0.729, 0.729) e) None of the above Question 9 Your answer is CORRECT This is a written question, worth 17 points. DO NOT place the problem code on the answer sheet. A proctor will fill this out after exam submission. Show all steps (work) on your answer sheet for full credit. Problem Code: 961 The belief is that the mean number of hours per week of part-time work of high school seniors in a city is 10.4 hours. Data from a simple random sample of 27 seniors indicated that their mean number of parttime work was 12.6 with a standard deviation of 1.2. Test whether these data cast doubt on the current belief. (use α = 0.05) Part a: State your null and alternative hypotheses. Part b: Sketch the rejection region. Part c: Calculate the test statistic. Plot this value in your sketch in part b. Part d: Determine the P-value for your test. Part e: State your conclusions clearly in complete sentences