Chapter 6: Q.16 (page 355)
Kids and toys Refer to Exercise 4. Calculate and interpret the standard deviation of the random variable . Show your work.
Short Answer
The number of toys played with is on average toys from the mean.
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Chapter 6: Q.16 (page 355)
Kids and toys Refer to Exercise 4. Calculate and interpret the standard deviation of the random variable . Show your work.
The number of toys played with is on average toys from the mean.
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Binomial setting? A binomial distribution will be approximately correct as a model for one of these two settings and not for the other. Explain why by briefly discussing both settings. (a) When an opinion poll calls residential telephone numbers at random, only of the calls reach a person. You watch the random digit dialing machine make calls. is the number that reaches a person
(b) When an opinion poll calls residential telephone numbers at random, only of the calls reach a live person. You watch the random digit dialing machine make calls. is the number of calls until the first live person answers
A large auto dealership keeps track of sales and leases agreements made during each hour of the day. Let = the number of cars sold and = the number of cars leased during the 铿乺st hour of business on a randomly selected Friday. Based on previous records, the probability distributions of and are as follows:

顿别铿乶别 .
Compute assuming that and are independent. Show your work
Keno is a favorite game in casinos, and similar games are popular in the states that operate lotteries. Balls numbered to are tumbled in a machine as the bets are placed, then of the balls are chosen at random. Players select numbers by marking a card. The simplest of the many wagers available is 鈥淢ark Number.鈥 Your payoff is on a bet if the number you select is one of those chosen. Because of numbers are chosen, your probability of winning is , or . Let the amount you gain on a single play of the game.
(a) Make a table that shows the probability distribution of .
(b) Compute the expected value of . Explain what this result means for the player
The length in inches of a cricket chosen at random from a field is a random variable with mean inches and standard deviation of inches. Find the mean and standard deviation of the length of a randomly chosen cricket from the field in centimeters. There are centimeters in an inch.
52. Study habits The academic motivation and study habits of female students as a group are better than those of males. The Survey of Study Habits and Attitudes is a psychological test that measures these factors. The distribution of scores among the women at a college has meanand standard deviation , and the distribution of scores among male students has mean and standard deviation You select a single male student and a single female student at random and give them the test.
(a) Explain why it is reasonable to assume that the scores of the two students are independent.
(b) What are the expected value and standard deviation of the difference (female minus male) between their scores?
(c) From the information given, can you find the probability that the woman chosen scores higher than the man? If so, find this probability. If not,
explain why you cannot.
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