Chapter 6: Q. 7. (page 367)
Get on the boat! Refer to Exercise 3. Find the mean of Y. Interpret this value.
Chapter 6: Q. 7. (page 367)
Get on the boat! Refer to Exercise 3. Find the mean of Y. Interpret this value.
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Get started for freeThe last kiss Do people have a preference for the last thing they taste?
Researchers at the University of Michigan designed a study to find out. The researchers gave 22 students five different Hershey's Kisses (milk chocolate, dark chocolate, crème, caramel, and almond) in random order and asked the student to rate each one. Participants were not told how many Kisses they would be tasting. However, when the 5th and final Kiss was presented, participants were told that it would be their last one. Assume that the participants in the study don't have a special preference for the last thing they taste. That is, assume that the probability a person would prefer the last Kiss tasted is .
a. Find the probability that 14 or more students would prefer the last Kiss tasted.
b. Of the 22 students, 14 gave the final Kiss the highest rating. Does this give convincing evidence that the participants have a preference for the last thing they taste?
Running a mile A study of able-bodied male students at the University of Illinois found that their times for the mile run were approximately Normal with mean minutes and standard deviation minute. 7 Choose a student at random from this group and call his time for the mile Y. Find . Interpret this value.
Housing in San José How do rented housing units differ from units occupied by their owners? Here are the distributions of the number of rooms for owner-occupied units and renter-occupied units in San José, California:
Let X= the number of rooms in a randomly selected owner-occupied unit and Y = the number of rooms in a randomly chosen renter-occupied unit.
(a) Here are histograms comparing the probability distributions of X and Y. Describe any differences you observe.
(b) Find the expected number of rooms for both types of housing unit. Explain why this difference makes sense.
(c) The standard deviations of the two random variables are and . Explain why this difference makes sense.
Random digit dialing When a polling company calls a telephone number at random, there is only a 9% chance that the call reaches a live person and the survey is successfully completed. 10 Suppose the random digit dialing machine makes 15 calls. Let X= the number of calls that result in a completed survey.
a. Find the probability that more than 12 calls are not completed.
b. Calculate and interpret .
c. Calculate and interpret .
Total gross profits on a randomly selected day at Tim’s Toys follow a distribution that is approximately Normal with mean and standard deviation . The cost of renting and maintaining the shop is per day. Let profit on a randomly selected day, so . Describe the shape, center, and variability of the probability distribution of .
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