practice quiz 7 and soln

practice quiz 7 and soln - (c) mean equal to 1.99 lb. and...

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Prequiz 7. PRACTICE QUESTIONS FOR QUIZ TODAY . NOVEMBER 2, 2003 1-2 A box of “1 lb.” weights must have a mean weight of 1 lb. with a standard deviation of 0.04 lb. _____1. We take a sample of n=100 weights and calculate the average of these. We let X denote the average of a sample of 100 "1 lb weights". Which statement is true of the distribution of X ? (a) mean equal to 1.0 lb. and standard deviation of 0.04 lb. (b) mean equal to 1.0 lb. and standard deviation of 0.01 lb. (c) mean equal to 1.99 lb. and standard deviation of 0.04 lb. (d) mean equal to 1.99 lb. and standard deviation of 0.01lb. _____ 2. We take a 1 lb. weight at random and X, denotes its weight. Which statement is true about the distribution of X? (a) mean equal to 1.0 lb. and standard deviation of 0.04 lb. (b) mean equal to 1.0 lb. and standard deviation of 0.01 lb.
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Unformatted text preview: (c) mean equal to 1.99 lb. and standard deviation of 0.04 lb. (d) mean equal to 1.99 lb. and standard deviation of 0.01lb. ____3. The probability that a random variable having the t distribution with 4 degrees of freedom is greater than -t 0.025 equals. (a) 0.025 (b) 0.975 (c) 0.05 (d) 0.95 ____ 4. Find t such that P(T 3 > t) = 0.05. Here T 3 denotes a random variable with the"t" p.d.f. and ν =3 . COMMON INFORMATION 5-7. Y k ~N(1,16) for k=1,2…25. The Y j are all pairwiseindependent. That is Cov(Y k , Y t )=0 for all k and t; μ Y =1, σ 2 y =16,n y =25 and let 25 25 1 ∑ = = k k Y Y . Let S 2 Y = 24 ) ( 2 25 1 ∑ =-k k Y Y . 5. Mean value of S 2 Y ( ANS. 16) 6.. Standard Error of Y 7. Pr( Y < 0) = Φ ( Z ) ; Z=_?____ ANS: 1. B 2. A 3. B 4. 2.353 5. 16 6. 0.8 7. -1.25 1...
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This homework help was uploaded on 01/31/2008 for the course AMS 310.01 taught by Professor Mendell during the Fall '03 term at SUNY Stony Brook.

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