Chapter 6: Q. 82 (page 358)
Taking the train Refer to Exercise 80 . Use the binomial probability formula to find . Interpret this value.
Short Answer
On selected days, there's a chance that 4 out of 7 trains will be late
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Chapter 6: Q. 82 (page 358)
Taking the train Refer to Exercise 80 . Use the binomial probability formula to find . Interpret this value.
On selected days, there's a chance that 4 out of 7 trains will be late
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Take a spin An online spinner has two colored regions_blue and yellow. According to the website, the probability that the spinner lands in the blue region on any spin is . Assume for now that this claim is correct. Suppose we spin the spinner 12 times and let the number of times it lands in the blue region.
a. Explain why is a binomial random variable.
b. Find the probability that exactly 8 spins land in the blue region.
Commuting to work Refer to Exercise 52 .
a. Assume that B and are independent random variables. Explain what this means in context.
b. Calculate and interpret the standard deviation of the difference (Bus - Walk) in the time it would take Sulé to get to work on a randomly selected day.
c. From the information given, can you find the probability that it will take Sulé longer to get to work on the bus than if he walks on a randomly selected day? Explain why or why not.
Standard deviations (6.1) Continuous random variables A, B, and C all take values between 0 and 10 . Their density curves, drawn on the same horizontal scales, are shown here. Rank the standard deviations of the three random variables from smallest to largest. Justify your answer.

Geometric or not? Determine whether each of the following scenarios describes a geometric setting. If so, define an appropriate geometric random variable.
a. Shuffle a standard deck of playing cards well. Then turn over one card at a time from the top of the deck until you get an ace.
b. Billy likes to play cornhole in his free time. On any toss, he has about a chance of getting a bag into the hole. As a challenge one day, Billy decides to keep tossing bags until he gets one in the hole.
The 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?
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