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180-2100 I. Multiple-choice (Circle the letter of your answer): = 100 and (1) For a continuous random variable 1, the population mean and standard deviation are o 20 respectively. the mean jy and the standard deviation og of the sample mean for a random sample of 16 items from this population are ( 5 0.05) (A) Pa = 25, ; 20 (B) P = 100, -20 (C) = 25,0 = 5 (D) Hg = 100, og = 5 (2) Suppose that 3% of the adults in a group have attempted suicide. Suppose a sample of 200 adults is selected at random from this group. The mean and the standard deviation of the sampling distribution for the sample proportion of the adults who have attempted suicide are: (A) = 0.03, ap = 0.00015 (B) Hp, = 0.03, p = 0.012 (C) P = 0.03, 0, -0.17 (D): 0.03, 0, = 0.97 (3) If the 95% confidence interval of the proportion of a population is (0.325, 0.375), which of the following are true? 1. The margin of of error is 0.05/2=0.025). II. The point estimate is 0.325 +0.025 = 0.35. III. The critical value 2/2 - 1.645. (A) I only (B) II only (C) I and II (D) I, II, and III Use the following information to answer questions 4-8: A very selective college claims that the mean GPA of its undergraduates is at least 3.125. A watch-dog group decides to test this hypothesis at the 5% level of significance. A random sample of 64 of their undergraduates indicates a mean of 2.987 with a standard deviation of 0.305. (O) To conduct a hypothesis test, you write the null and alternative hypotheses as follows: (A) H : 23.125 H: <3.125 (B) HONS 3.125 H : > 3.125 (C) Hạ 4 2 2 897 H BA < 2,897 (D) H: <2 897 H 4 >22597 (5) The degrees of freedom for the test statistic t in this situation are: (A) df = n 8 (B) dan +1 = 65 (C) df = n = 64 (D) df = n-1=63 (6) Which of the following is the correct critical value of t for a = 5%, ? (A) to as = -1.671 for a left-tailed t-test (B) to cs 1.671 for a right-tailed t-test (C) 10.025 = 2.000 for a two-tailed t-test (D) Cannot be determined. (7) The value of the t-statistic from the sample data is (A) -0.138 (B) -0.038 (C) -3.62 (D) cannot be determined. (8) At the level of significance 0.05, which of the following is the correct conclusion to the problem? (A) =-3.62 falls in the rejection region for a left-tailed test, reject the null hypothesis. (B) ly = -3.62 falls in the non-rejection region for a right-tailed test, fail to reject the mall hypothesis (C) -3.62 falls in the rejection region for a two-tailed test, reject the null hypothesis (D) Cannot be determined. (9) Which of the following describes a correct effect on which the width of a confidence interval? I. As sample size increases, the width decreases. II. As the confidence level increases, the width increases. III. As the standard deviation of the estimates increases, the width increases (A) I only (B) II only (C) I and II (D) I, II, and III (10) If the P-value of a test is less than the significance level , which of the following is a correct conclusion? (A) The null hypothesis is false. (B) The alternative hypothesis is true. (C) Reject the null hypothesis. (D) All of the above

Answer 1

DATE Given 8 P=0.03 n-200 -P=0.97 Mean std den of TOPHon ③ 8 - 10.031 Ê = ? (1-8). 10.05x0.97 -0.0121 only opHon Because is 1.96 I is corong 2012 at 95.1. confidence level Hence option @

PAGE No. DATE alven : 4=100, =20 n=16 XNN(4=100,- 208 The sampling disth of x 00.0 XN NC 45 -100, j = 0 - 20 - 5) Nov16 VN N(4x=100, 8x = 5) Ophono