Question

_ 9) In a sample of 10 randomly selected women, it was found that their mean height was 634 inches. From previous studies, it is assumed that the standard deviation, , 124 inches and that the population of height measurements is normally distributed a) Construct the confidence interval for the population mean height of women b) If the sample size was doubled to 20 women, what will be the effect on the confidence interval? 10) 10) The numbers of advertisements seen or heard in one week for 30 randomly selected people in the United States are listed below. Construct a 95% confidence interval for the true mean number of advertisements. Assume that is 1995 598 494 441 595 728 690 684 486 235 481296 734 588 135 590 846 540 766 673 317 727 649 565 732 486 58267 202 203 11) The grade point averages for 10 randomly selected students in a statistics class with 125 students are listed below. 11) 2.0 3.2 1.8 2.9 0.9 4.0 3.3 2.9 3.6 08 What is the effect on the width of the confidence interval if the sample size is increased to 207 Explain your reasoning. MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answer the question. 12) The P-value for a hypothesis test is P-0.034. Do you reject or fail to reject Ho when the level 12) of significance is a 0.01? A) reject Ho B) not sufficient information to decide C) fail to reject Ho 13) Find the P-value for the hypothesis test with the standardized test statistica. Decide whether to reject Ho for the level of significance a. 13) Right-tailed test 20.52 0.05 A) 0.6000; Fail to reject Ho 0.3015; Reject Ho B) 0.0195, Reject Ho D) 0:3015: Fail to reject Ho

Answer 1

9 given m = 10 X-69.4 o -2.4 a) let los be d = 0·0), z = 3.58 99%. C' I & Xt = 63.4 $ 2. = 63-4 £ 1.958 = (61.44, 65.358) If we increase the sample slze then the width of the confidence interval decreases. 994.c.1 = m=20 63.4 2 2.58 (ay) 120 = 63.4 ± 1.385 - (62.015, 64.785)