38. Which statement(s) below concerning two normal distribution curves are necessarily true? VI. Two normal curves can have the same mean, but different standard deviations. MII. Two normal curves can have the same standard deviation, but different means. x III. For two normal curves, the curve with the larger mean must also have the larger standard deviation. (A) I only (B) II only (C) III only (D) I and II only (E) I, II, and III AnswerSection I Sample Examination Three 65 19. The admissions policy at a certain university requires that incoming students score in the upper 20% on a standardized test. If the mean score on the test is 510 and the standard deviation of the scores is 80, what is the minimum score that a student can earn on the test to meet the admissions requirement? Scores on the test are normally distributed and are reported in intervals of 10. (A) 520 (B) 580 (C) 590 (D) 600 620 Answer108 Sample Examination Five Section I 8. The mean score on a nationally used standardized reading exam was 75 with a standard deviation of four. What would be the z-score for a child who scored an 81? (A) -1.5 B) -1.03 (C) 1.03 (D) 1.05 (E) 1.5 Answer(E) $5.00 $ 5 Answer ALL. JIMININLO LAAM JI -105 7. Grades on a statistics test are normally distributed with a mean of 76 and a standard deviation of 8. Our teacher will give the top 10% an A, the next 20% a B, the next 40% a C, the next 20% a D, and the bottom 10% an F. The students who received F's in the course had no higher than (A) 65.75 69.24 (C) 71.84 e 80.1 86.4 Answer Unauthorized copying or re any part of this page is IllC) The distribution D) The distribution is most likely skewed to the right. (E) This is a uniform distribution. Answer 4. The scores on the real estate licensing examination given in a particular state are normally distributed with a standard deviation of 70. What is the mean test score if 25% of the applicants score above 475? (A) 416 75 #434 75 428 (C) 468 e 522 There is not enough information to answer this question Answer(E) 0.9332 911 Answer 21. A survey was taken to determine the number of hours per week students studied mathematics. The distribution was approximately normal with a mean of 20 hours and a standard deviation of four hours. Approximately what percent of the students studied between 27 and 30 hours? (A) 0.00338% B) 0.004594 (C) 0.4937% D) 3.39% E) 4.937% Answer 22. Size AAA batteries have a mean life of two years with a standard deviation of six months. The life spans of AAA batteries are normally distributed. If the money-back guarantee allows you to return the batteries if they do not last at least eight months, what is the probability that a randomly selected battery will qualify for the guarantee? (A) 0.0038 B) 0.0049(C) 0.4937% (D) 3.39% E 4.937% Answer 22. Size AAA batteries have a mean life of two years with a standard deviation of six months. The life spans of AAA batteries are normally distributed. If the money-back guarantee allows you to return the batteries if they do not last at least eight months, what is the probability that a randomly selected battery will qualify for the guarantee? (A) 0.0038 B) 0.0049 (C) 0.3800 (D) 0.4900 (E 0.4962 Answer Unauthorized copying or reusing any part of this page Is Illegal.Section I Sample Examination Four 23. A normal distribution has a mean / and a variance of 16. If the 35th percentile is equal to 8, then / is approximately equal to A) -2.29 -1.03 0.29 9.55 10.67 Answer 24. A simple random sample of 150 policemen found that the average time these men had worked for the police department was x = 18 years with a standard deviation s = 3 years. Assume the distribution of the time the population of men has worked for the police approximately normal with mean u. Ten years ago the average amountSection I Sample Examination Six 141 22. The mean of a set of data is 40 pounds and the standard deviation is 8 pounds. What value of an observation corresponds to a z-score of -1.25? (A) -30 B) - 50 (C) 30 (D) 32 (E) 40 48 50 Answer 23. Suppose you select a random sample of size 5 from a normal distribution with unknown mean u and unknown variance 2. The null hypothesis Ho: / = 65 is to be tested against the alternative hypothesis Ha : (#65 at a = 0.05. If the resulting sample mean is 68.25 and s2= 9, what is the value of the appropriate test statistic and the conclusion?by a few outlying observations. Ansv 7. If the standard deviation of a set of data is zero, we can conclude that (A) an error in computation was made B) the observations are equally spaced (C) it was not a simple random sample (D) the mean must also be zero all the observations are the same Ans Unauthorized copyin any part of this pac21, A survey was taken to determine the number of hours per week students studied mathematics. The distribution was approximately normal with a mean of 20 hours and a standard deviation of four hours. Approximately what percent of the students studied between 27 and 30 hours? (A) 0.00338% (B) 0.004594 (C) 0.4937% (D) 3.39% (E) 4.937% AnswerSection 1 Sample Examination Four 89 18. A distribution that is symmetric and mound-shaped has a mean of 30 and a standard between deviation of 2. According to the Empirical Rule, approximately 68% of the data lie (A) 24 and 36 (B) 26 and 34 (C) 28 and 32 (D) 20 and 40 (E) 25 and 35 Answer 19. The figure below shows the probability density functions of two symmetric distributions with the same mean. _B Which of the following statements are true? (A) median A > median B; OA= OB (B) median A OB (C) median A = median B; OA> OB (D) median A = median B; OA