STAT302 Secs 507 509 Spring 1998 Exam 2 Form A Instructor Julie Hagen Carroll 1 Don t even open this until you are told to do so 2 Be sure to mark your section number 507 508 or 509 and your test form A B C or D on the scantron 3 Sign your name where indicated on your scantron and write your Tuesday section number and computer number beside it Also you must place your scantron in the correct section stack for next Tuesday 4 There are 20 multiple choice questions on this exam each worth 5 points There is partial credit Please mark your answers clearly on the scantron Multiple marks will be counted wrong 5 You will have 60 minutes to finish this exam 6 If you are caught cheating or helping someone to cheat on this exam you both will receive a grade of zero on the exam You must work alone 7 This exam is worth 100 points and will constitute 25 of your final grade 8 Good luck 1 STAT302 507 509 Exam 2 Form A Spring 1998 D There is a 3 8 chance of making a Type I error E None of the above are appropriate 1 What is the power of the test represented in the graph above A B C D E 0 511 0 05 0 95 0 489 Since H0 is true there is no chance of a Type II error 5 What is the correct conclusion based on the graph above A Reject H0 at the 10 level and conclude that the true proportion is not 0 5 B Reject H0 at the 10 level and conclude that the true proportion is greater than 0 1 C Reject H0 at the 10 level and conclude that the true proportion is greater than 0 7 D Reject H0 at the 10 level and conclude that the true proportion is greater than 0 5 E Reject H0 at the 10 level and conclude that the true proportion is not 0 7 2 Which of the following would change the power of the test A B C D E reducing the significance level reducing the sample size n reducing the chance of a Type II error All of the above Exactly two of the above excluding D 6 Suppose we want to find out whether Aggies GPR s improve throughout their college career Which of the following would be the best method to test this hypothesis 3 What is the purpose of confidence intervals A to give us a range of plausible values for the sample statistic B to give us a range of plausible values for the population parameter C to give us a range of values to find the probability for since a continuous distribution has no probability at any one point D to test whether a hypothesis is true E to test if we know what we re doing A Take two independent random samples one of freshmen and one of seniors and compare their average GPR s B Take two independent random samples one of freshmen and one of seniors and calculate the proportion that had higher GPR s C Take a random sample of seniors find the difference in their GPR s as freshmen and as seniors and compare that to zero D Take a random sample of seniors find their average GPR and compare that to zero E Take a random sample of seniors find their average GPR and compare that to their average GPR as freshmen 4 Suppose we conducted a two sided hypothesis for H0 1 2 and found the p value 0 038 What is the best interpretation of this value A There is a 3 8 chance of getting a difference in sample means as large as we got or more and the true means still being equal B There is a 3 8 chance of rejecting H0 C There is a 3 8 chance of not rejecting H0 2 STAT302 507 509 Exam 2 Form A 10 Which of the following is the best interpretation of in a test of hypotheses Level Mean Std Err Conf Interval 90 22 7 1 032371 20 9098 24 4902 95 22 7 1 032371 20 5311 24 8689 99 22 7 1 032371 19 7284 25 6716 A is the proportion of times you will reject H0 B is the proportion of times you will fail to reject H0 C is the proportion of times the hypothesized value will fall outside a 1 confidence interval D is the proportion of times the hypothesized value will fall inside a 1 confidence interval E is the proportion of times you will make a Type I error 7 What is the correct range of the p value for testing H0 24 5 vs HA 6 24 5 A B C D E Spring 1998 p value 0 10 0 10 p value 0 05 0 05 p value 0 01 p value 0 01 You need a test statistic value to determine the p value 8 What would be the result of a making a Type I error in the hypothesis test above H0 24 5 vs HA 6 24 5 A 13 B 13 C 13 A You conclude that the true mean is 24 5 when it actually is not 24 5 B You conclude that the true mean is 24 5 when it actually is 24 5 C You conclude that the true mean is not 24 5 when it actually is 24 5 D You conclude that the true mean is not 24 5 when it actually is not 24 5 E You can t make a Type I error unless you fail to reject H0 5 8 5 8 5 8 1 004007 1 004007 1 004007 4 01057 2 73322 3 61245 7 58943 8 86678 7 98754 11 Which of the following is correct A B C D E A is the 90 B is the 95 C B is the 90 C is the 95 A A is the 90 C is the 95 B B is the 90 A is the 95 C C is the 90 B is the 95 A is is is is is the the the the the 99 99 99 99 99 9 Again referring to the previous data what is the best interpretation of the 90 confidence interval A 90 of the time the true mean will fall in this interval B If we could generate all possible 90 confidence intervals for this population 90 of them would be 20 9098 24 4902 C If we could generate all possible 90 confidence intervals for this population 90 of them would have between 20 9098 24 4902 D If we could generate all possible 90 confidence intervals for this population 90 of them would contain E None of the above are correct 12 What are the hypotheses being tested in the graph above A B C D E 3 H0 H0 H0 H0 H0 1 2 1 vs HA 1 2 6 1 12 22 1 vs HA 12 22 6 …