# HW5 - STAT 350 Homework#5 SOLUTION Text Exercises Chapter...

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STAT 350 – Homework #5 SOLUTION Text Exercises Chapter 7 #38, 46, 48, 52 Chapter 8 #10, 12, 14, 18, 22, 26, 40, 56, 58 (this problem was un-assigned) 7.38 () 0.05/ 2,8 1 3.1 30.2 2.365 27.608,32.792 8 s xt n ±⇒ ± 7.46 22 11 2 2 12 0.66 20 0.741194487 0.66 0.39 20 20 sn c ss nn == = + + ( ) ( ) 2 2 21 2 2 df 1 20 1 20 1 30.83 20 1 0.741194487 20 1 1 0.741194487 nc n c −− = −+ df is rounded down to 30. thus t * = 2.042 * / 2 0.66 0.39 8.74 4.96 2.042 3.43,4.13 20 20 xxt α −± + ⇒ − ± +

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7.48 a high middle 470 460 450 440 430 420 Data Boxplot of middle, high b. Total Variable Count Mean StDev middle 17 438.29 15.14 high 11 437.45 6.83 22 11 2 2 12 15.14 17 0.760734951 15.14 6.83 17 11 sn c ss nn == = + + () ( ) ( ) 2 2 21 2 2 df 1 17 1 11 1 23.869 11 1 0.760734951 17 1 1 0.760734951 nc n c −− = −+ df is rounded down to 23 thus t * = 2.069 * / 2 15.14 6.83 438.29 437.45 2.069 17 11 7.87,9.55 xxt α −± + ⇒ ± + ⇒− The fact that the confidence interval for the difference in the means includes zero suggests that we cannot say with confidence that there is a true difference in the means of these two populations.
7.52 House: Indoor: Outdoor: difference 1 0.07 0.29 -0.22 2 0.08 0.09 -0.01 3 0.09 0.47 -0.38 4 0.12 0.54 -0.42 5 0.12 0.97 -0.85 6 0.12 0.35 -0.23 7 0.13 0.49 -0.36 8 0.14 0.84 -0.70 9 0.15 0.86 -0.71 10 0.15 0.28 -0.13 11 0.17 0.32 -0.15 12 0.17 0.32 -0.15 13 0.18 1.55 -1.37 14 0.18 0.66 -0.48 15 0.18 0.29 -0.11 16 0.18 0.21 -0.03 17 0.19 1.02 -0.83 18 0.20 1.59 -1.39 19 0.22 0.90 -0.68 20 0.22 0.52 -0.30 21 0.23 0.12 0.11 22 0.23 0.54 -0.31 23 0.25 0.88

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## This note was uploaded on 03/09/2010 for the course STAT 350 taught by Professor Staff during the Spring '08 term at Purdue.

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HW5 - STAT 350 Homework#5 SOLUTION Text Exercises Chapter...

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