Let X and Y equal the respective numbers of hours a randomly selected child watches movies or cartoons on TV during a certain month. From experience, it is known that E(X) = 30, E(Y) = 50, Var(X) = 52, Var(Y) = 64, and Cov(X, Y) = 14. Twenty-five children are selected at random. Let Z equal the total number of hours these 25 children watch TV movies or cartoons in the next month. Approximate P(1970 < Z < 2090). Hint: Use the remark after Theorem 5.3-2.
Answer to relevant QuestionsAt certain times during the year, a bus company runs a special van holding 10 passengers from Iowa City to Chicago. After the opening of sales of the tickets, the time (in minutes) between sales of tickets for the trip has a ...Let X equal the weight in grams of a miniature candy bar. Assume that μ = E(X) = 24.43 and σ2 = Var(X) = 2.20. Let X be the sample mean of a random sample of n = 30 candy bars. Find (a) E(X). (b) Var(X). (c) P(24.17 ≤ ...Let X equal the number out of n = 48 mature aster seeds that will germinate when p = 0.75 is the probability that a particular seed germinates. Approximate P(35 ≤ X ≤ 40). In 1985, Kent Hrbek of the Minnesota Twins and Dion James of the Milwaukee Brewers had the following numbers of hits (H) and official at bats (AB) on grass and artificial turf: (a) Find the batting average BA (namely, H/AB) ...Nine measurements are taken on the strength of a certain metal. In order, they are 7.2, 8.9, 9.7, 10.5, 10.9, 11.7, 12.9, 13.9, 15.3, and these values correspond to the 10th, 20th, . . . , 90th percentiles of this sample. ...
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