pracexamquesfall20083a

pracexamquesfall20083a - Practice Exam Questions and...

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Practice Exam Questions and Solutions for the Final Exam; Fall, 2008 Statistics 301, Professor Wardrop Part B, Chapters 16, 8 and 13 Chapter 16 1. Independent random samples are selected from two populations. Below are selected summary statistics. Pop. Mean Stand. Dev. Sample size 1 62.00 10.00 17 2 54.00 6.00 10 (a) Calculate s p . (b) Calculate the 90% CI for μ X μ Y . Use Case 1. 2. Independent random samples are selected from two populations. Below are selected summary statistics. ¯ x = 22 . 50 , s X = 3 . 75 and n 1 = 18 ¯ y = 16 . 25 , s Y = 8 . 50 and n 2 = 6 (a) Calculate s p . (b) Calculate the 98% CI for μ X μ Y . Use Case 1. 3. The null hypothesis is μ X = μ Y . Use Case 1 from Section 16.2 to obtain the P-value for each of the situations described below. (a) The alternative is μ X > μ Y ; the value of the test statistic is 1.840; the sample sizes are 5 and 5. (b) The alternative is μ X < μ Y ; the value of the test statistic is 3 . 150 ; the sample sizes are 6 and 7. (c) The alternative is μ X n = μ Y ; the value of the test statistic is 1.341; the sample sizes are 5 and 12. (d) The alternative is μ X n = μ Y ; the value of the test statistic is 0 . 641 ; the sample sizes are 12 and 12. 4. The null hypothesis is μ X = μ Y . Use Case 1 from Section 16.2 to obtain the P-value for each of the situations described below. (a) The alternative is μ X > μ Y ; the value of the test statistic is 0.690; the sample sizes are 4 and 4. (b) The alternative is μ X < μ Y ; the value of the test statistic is 1 . 796 ; the sample sizes are 6 and 7. (c) The alternative is μ X n = μ Y ; the value of the test statistic is 1.850; the sample sizes are 7 and 14. (d) The alternative is μ X n = μ Y ; the value of the test statistic is 3 . 641 ; the sample sizes are 4 and 12. 5. Mike performs a study with n 1 = 10 and n 2 = 6 . Using Case 1 from Section 16.2, he calcu- lates an 80% CI for μ X μ Y and obtains: [6 . 000 , 14 . 000] . Calculate the 95% CI for μ X μ Y for Mike’s data. 6. Maria performs a study with n 1 = 14 and n 2 = 12 . Using Case 1 from Section 16.2, she calculates a 90% CI for μ X μ Y and obtains: [9 . 500 , 18 . 500] . Calculate the 99% CI for μ X μ Y for Maria’s data. Chapter 8 7. Below is the table of population counts for a dis- ease and its screening test. (Recall that A means the disease is present and B means the screen- ing test is positive.) On parts (a)–(e) below, re- port your answers as a decimal to three digits of precision, for example 0.231. B B c Total A 108 12 120 A c 42 698 740 Total 150 710 860 1
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(a) What proportion of the population is free of the disease? (b) What proportion of the population has the
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pracexamquesfall20083a - Practice Exam Questions and...

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