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Unformatted text preview: EON317 Midterm Examination #3 Form B Professor Manochehr Rashidian April 22, 2008 1. (25 POINTS) Let μ 1 , μ 2 and μ 3 denote the mean tire life (in 1,000 miles) of Goodyear, Toyo, and General, respectively. The null and the alternative hypotheses are H : μ 1 = μ 2 = μ 3 , H a : The mean lives differ for at least two of the brands. Since ¯ x = 66 . 6364 , SST = n 1 (¯ x 1 ¯ x ) 2 + n 2 (¯ x 2 ¯ x ) 2 + n 3 (¯ x 3 ¯ x ) = 4(62 66 . 6364) 2 + 3(67 66 . 6364) 2 + 4(71 66 . 6364) 2 = 162 . 5455 , SSE = ( n 1 1) s 2 1 + ( n 2 1) s 2 2 + ( n 3 1) s 2 3 = 3(9 . 6609) 2 + 2(5) 2 + 3(3 . 7417) 2 = 372 , MST = SST p 1 = 162 . 5455 3 1 = 81 . 2727 , MSE = SSE n p = 652 11 3 = 46 . 5 , a test statistic F = MST MSE = 1 . 7478 . The critical value F . 05 = 4 . 46. So we FAIL to reject the null hypothesis. There is no evidence that the mean tire lives differ for at least two of the brands. 1 2. (25 POINTS) Let n 1 and n 2 denote the number of samples from ad justable rate mortgages and fixed rate mortgages. Assuming the equal size of sampling, n 1 = n 2 = n , B = z . 05 / 2 r p 1 q 1 n + p 2 q 2 n ⇒ . 08 2 = 1 . 96 r ( . 5)( . 5) n + ( . 5)( . 5) n ⇒ n = n 1 = n 2 = (1 . 96) 2 (( . 5)( . 5) + ( . 5)( . 5)) . 04 2 = 1200 . 5 . Therefore we need n 1 = n 2 = 1201....
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This note was uploaded on 09/11/2008 for the course ECON 317 taught by Professor Safarzadeh during the Spring '07 term at USC.
 Spring '07
 Safarzadeh

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