Chapter 4: Discrete Random Variables
Q. 4.24
A palette has 200 milk cartons. Of the 200 cartons, it is known that ten of them have leaked and cannot be sold. A stock clerk randomly chooses 18 for inspection. He wants to know the probability that among the 18, no more than two are leaking. Give five reasons why this is a hypergeometric problem.
Q. 4.26
The average number of fish caught in an hour is eight. Of interest is the number of fish caught in 15 minutes. The time interval of interest is 15 minutes. What is the average number of fish caught in 15 minutes?
Q. 4.27
An electronics store expects to have ten returns per day on average. The manager wants to know the probability of the store getting fewer than eight returns on any given day. State the probability question mathematically.
Q. 4.28
An emergency room at a particular hospital gets an average of five patients per hour. A doctor wants to know the probability that the ER gets more than five patients per hour. Give the reason why this would be a Poisson distribution.
Q. 4.29
A customer service center receives about ten emails every half-hour. What is the probability that the customer service center receives more than four emails in the next six minutes? Use the TI-83+ or TI-84 calculator to find the answer.
Q. 43
Use the following information to answer the next eight exercises: The Higher Education Research Institute at UCLA collected data from incoming first-time, full-time freshmen from 270 four-year colleges and universities in the U.S. of those students replied that, yes, they believe that same-sex couples should have the right to legal marital status. Suppose that you randomly pick eight first-time, full-time freshmen from the survey. You are interested in the number that believes that same sex-couples should have the right to legal marital status.
What is the probability that at most five of the freshmen reply鈥测别蝉鈥?
Q. 44
Use the following information to answer the next eight exercises: The Higher Education Research Institute at UCLA collected data from incoming first-time, full-time freshmen from four-year colleges and universities in theU.S. of those students replied that, yes, they believe that same-sex couples should have the right to legal marital status. Suppose that you randomly pick eight first-time, full-time freshmen from the survey. You are interested in the number that believes that same sex-couples should have the right to legal marital status.
What is the probability that at least two of the freshmen reply鈥测别蝉鈥?
Q.4.4
A hospital researcher is interested in the number of times the average post-op patient will ring the nurse during a 12-hour shift. For a random sample of 50 patients, the following information was obtained. What is the expected value?

Q.4.5
You are playing a game of chance in which four cards are drawn from a standard deck of 52 cards. You guess the suit of each card before it is drawn. The cards are replaced in the deck on each draw. You pay \(1 to play. If you guess the right suit every time, you get your money back and \)256. What is your expected profit of playing the game over the long term?
Q.4.6
Suppose you play a game with a spinner. You play each game by spinning the spinner once. P(red) = , P(blue) = , and P(green) = . If you land on red, you pay . If you land on blue, you don't pay or win anything. If you land on green, you win . Complete the following expected value table.