Stats 2 week 10

Stats 2 week 10 - You give the value y when x = 6 a The...

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Sarah Anderson Stats 2 Week 10 Exercises 28(pages 482 – 483) Exercise 32 (pages 485 – 486) 34 (pages 490 – 491) 15.a. E(X-X)(Y-Y) =44.6, sx = 2.726, sy =2.011 r = 44.6/(10-1)(2.726)(2.011) =.904 b= .904(2.011/2.726) =.667 a= 7.4 - .677(9.1) = 1.333 b. Y = 1.333 + .667(6) = 5.335 17. b. E(X-X)(Y-Y) = 629.64, sx = 26.17, sy = 3.248 r= 629.64/(12-1)(26.17)(3.248) = .6734 c. r2 = (0.673)^2 = 0.4529 d. A strong positive association between the variables. About 45 percent of the variation in earnings is accounted for by sales. e. b= .6734 (3.248/26.170) = 0.0836 a= 64.1/12 - .0836 (501.10/12) = 1.8507 0 10 20 30 40 50 60 70 80 90 100 0 2 4 6 8 10 12 14 Column B

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f. Y= 1.8507 + .0836(50.0) = 6.0307(\$ millions) 22. Determine the value of Y when X is 7.
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Unformatted text preview: You give the value y when x = 6. a) The regression is such that the mean error is minimal, The (standard) error (of estimate) = sqrt[sum( y(calculated) - y(measured))^2/N] is minimal. = sqrt(mean(y²) - (mean(y))²) = Σy² = 169+225+49+144+169+121+81+25) = 983 error = sqrt(123 - 10.6²) = 3.26 b) When more samples were taken most of the predictions would be within y = calculated +/- 2 * standard deviation. (is calculated value +/- 6.5) 23. a. sq root 6.667/10-2 = .913 b. Y +- 1.826 28. 29.a. 4.2939, 6.3721 b. 2.9854, 7.6806 32. 33.a. r2 = 1,000/1500 =.667 b. .82, found by sq root of .667 c. 6.20, found by sy*x = sq root of 500/15-2 34....
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Stats 2 week 10 - You give the value y when x = 6 a The...

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