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Unformatted text preview: Statistics I Jun Nie RCT: Tues 2 3:15 Homework 6 Section 62: 4, 6, 8, 12, 16, 18, 24, 30, 32, 36, 40 4. The Bell Shape is a symmetrical hill with the peak at Z = 0, and tapers off to both sides, approaching zero. The area of the function from  to + approaches 1. 6. p( x > 50.5) = 3* .5 * .5 = .75 8. 51.6 51.5 = .1 minutes (.1 / 2) = .05 12. p( Z < 2.5) = .9946 18. p( 0.50 < Z < 1.50 ) = p( Z < 1.5) p( Z < 0.50) = .9932  .6915 = .3107 24. p( 3.90 < Z < 1.50) p( Z < 1.50) = .9932 {because p( Z < 3.90) << 0.001} 30. p(2 < Z < 2) = 1  2p( Z < 2) = 1 2(.0228) = .9544 95.44% 32. p(3.50 < Z < 3.50) = 1  2p( Z < 3.50) = 1 2(.0001) = .9998 99.98% 36. p( Z > 1.96) = 2p(Z < 1.96) = 2(.025) = .05 40. We reject 1% of thermometers that read too high and 1% that read too low. We select the middle 98%. We define: Z* = upper bound, Z* = lower bound. We accept values of Z that fulfill the following inequality: Z < Z* , where p(Z < Z*) = .98 p(Z < Z*) = p(Z > Z*) = .01, we solve for Z*. According to the ZScore table, we get Z* 2.33 . {According to a ttable with an area of .02 in two tails, and a large degree of freedom, we arrive at Z* = 2.326} The two reading cutoff values are 2.33 and 2.33 for the upper and lower bounds, respectively. Section 63: 6, 12, 16, 18, 22, 30 6. = 100, = 15, X = 131.5 Z = (x ) / (131.5 100) / 15= 2.10 p(Z > 2.10) = .0179 12. p(Z > Z) = .15 Z 1.04 X = ()( Z*) + = (15)(1.04) + 100 = 115.6 16. given: mens height = 69, = 2.8, womens height = 63.6, = 2.5 a....
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This note was uploaded on 08/27/2008 for the course ECON V31.0018 taught by Professor Hall during the Spring '08 term at NYU.
 Spring '08
 Hall

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