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# practice3 - Practice Problems 3(Second half of Course 1 A...

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Practice Problems 3 (Second half of Course) 1. A sample of 320 union members showed their missed work time due to illness during the past month averaged 9.6 hours with a standard deviation of 6.4 hours. A 90% confidence interval for the true mean number of hours or work union members missed last month due to illness is (A) ; 320 4 . 6 ) 96 . 1 ( 6 . 9 ± (B) ; ) 4 . 6 )( 96 . 1 ( 6 . 9 ± (C) ; 320 4 . 6 ) 645 . 1 ( 6 . 9 ± (D) ; ) 4 . 6 )( 645 . 1 ( 6 . 9 ± (E) None of the above 2. If a hypothesis test rejects H o at α = .10, then (A) a type I error has been committed; (B) a type II error has been committed; (C) p-value < .10; (D) both (A) and (B) (E) None of the above 3. A population has a mean of 25. If 100 samples are selected from this population and each one is used to form a 95% confidence interval for μ , how many of these intervals would you expect to contain 25? (A) 100; (B) 95; (C) 90; (D) 25; (E) None of the above 4. If a hypothesis test rejects H o , then (A) it is not possible that the test committed a type I error; (B) it is not possible that the test committed a type II error; (C) H o must be true;

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(D) H o must be false; (E) Both (A) and (B). The following information is for the next two questions: A criminal trail is, essentially, a test of H o : The defendant is innocent vs. H A : The defendant is guilty. The jury may decide to convict the defendant (i.e., reject H o ) or to acquit the defendant (i.e., not reject H o ). Suppose that, overall, 18% of guilty defendants are acquitted and 3% of innocent defendants are convicted. 5. The probability that the jury will commit a type I error is (A) 0.05; (B) 0.03; (C) 0.97; (D) 0.82 (E) None of the above 6. The probability that the jury will commit a type II error is (A) 0.18 (B) 0.82 (C) 0.03 (D) 0.97 (E) None of the above The following information is for the next 4 questions: Wilshaw of Agrow Limited has developed a revolutionary foliar feed for tomato plants. He is confident that the use of this feed will increase the yield of tomatoes from plants of one particular variety. In a preliminary trial the yields in kg of 12 plants given the foliar feed were: 3.2 4.1 4.9 4.6 3.8 4.9 4.3 3.9 4.7 5.2 3.5 4.4 7. Which of the following is the standard deviation of the 12 yields, to three decimal places? (A) 0.341 kg (B) 0.372 kg
(C) 0.584 kg (D) 0.610 kg 8. Which of the following is the range of the 12 yields? (A) 1.4 kg (B) 1.7 kg (C) 2.0 kg (D) 4.2 kg 9. Which of the following are 95% confidence limits for the mean yield of all tomato plants of this variety when fed with this foliar feed? (A) 0.36 to 8.94 kg (B) 3.82 to 4.76 kg (C) 3.90 to 4.68 kg (D) 4.18 to 4.40 kg 10. In the light of the variation in yield from plant to plant, how many plants would be needed to estimate the true mean yield to within ± 0.1 kg? (A) 14

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practice3 - Practice Problems 3(Second half of Course 1 A...

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