- Question 5 4 Marks A Manufacturing Company Produces Electric Insulators From Historical Measurements It Is Known That 1 (122.62 KiB) Viewed 35 times
- Question 5 4 Marks A Manufacturing Company Produces Electric Insulators From Historical Measurements It Is Known That 2 (100.68 KiB) Viewed 35 times
Question 5 (4 marks) A manufacturing company produces electric insulators. From historical measurements it is known that the breaking strength of the insulators follows a normal distribution with a mean force in pounds) required to break the insulator of 1750 pounds. As part of the quality control process, the manager must test if there are any changes in the breaking strength of the insulators. For a sample of 60 insulators, the force required to break the insulators yielded a mean and standard deviation of 1733.4 pounds and 89.55 pounds, respectively. For each one of the following questions, select the correct answer from the list below. 5.1 (1 mark) Define the correct null hypothesis A. Ho u = 1733.4 v 5.2 (1 mark) Define the correct form of the alternative B. Ho H = 1750.0 hypothesis. C. One-side test to the left 5.3 (1 mark) If the population variance is unknown, calculate the test statistic (to 3 decimal places). D. One-side test to the right E. Two-sided 5.4 (1 mark) If the population variance is known to be equal to 7744, calculate the test statistic (to 3 decimal places). F. -0.016 G.-0.017 H. -1.436 1.-1.461 QUESTION 6 Question 6 (4 marks) For each of the following hypothesis tests, calculate the p-value, correct to 4 decimal places. 6.1 (2 marks) For a two-sided hypothesis test for a one-sample z, the test statistic was found to be -1.22. D-value = 6.2 (2 marks) For a one-sided hypothesis test to the right for a one-sample proportion, the test statistic was found to be +1.45. p-value =
Question 7 (4 marks) For each one of the following questions, select the correct answer from the list below. ✓ 7.1 (2 marks) For a two-sided hypothesis test the critical values A. Reject the null hypothesis are +1.96 and -1.96. The test statistic is equal to 2.5. State the decision about Ho B. Fail to reject the null hypothesis - 7.1(2 marks) For a two-sided hypothesis test the critical values C. There is sufficient evidence for the alternative hypothesis are +1.96 and -1.96. The test statistic is equal to 2.5. State the p. There is insufficient evidence for the alternative hypothesis conclusion about H1 7.2 (2 marks) For a right-tailed hypothesis test the critical value is equal to +2.445 and the test statistic is equal to +1.79. State the decision about Ho 7.2 (2 marks) For a right-tailed hypothesis test the critical value is equal to +2.445 and the test statistic is equal to +1.79. State the conclusion about H1 QUESTION 8 Question 8 (1 mark) The HR director of a company noted that in previous years absenteeism due to illness among clerical workers at their Johannesburg office is assumed to be normally distributed with a mean of 10 days. He instituted a program at work to improve the health and wellness of employees. After one year he selected a random sample of 16 clerical workers and found the mean number of days absent to be 8.5 days with a standard deviation of 4 days. In testing this hypothesis at the 10% level of significance, what is the absolute value of the critical value, correct to 3 decimal places? Do not include the sign in your answer. Absolute value of critical value =