Chapter 4: Q.30 (page 285)
P(x = 4) = _______
1
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Suppose that about 85% of graduating students attend their graduation. A group of 22 graduating students is randomly chosen.
a. In words, define the random variable X.
b. List the values that X may take on.
c. Give the distribution of X. X ~ _____(_____,_____)
d. How many are expected to attend their graduation?
e. Find the probability that 17 or 18 attend.
f. Based on numerical values, would you be surprised if all 22 attended graduation? Justify your answer numerically
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.
You throw darts at a board until you hit the center area. Your probability of hitting the center area is p = 0.17. You want to find the probability that it takes eight throws until you hit the center. What values does X take on?
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?
The chance of an IRS audit for a tax return with over in income is about per year. Suppose that people
with tax returns over are randomly picked. We are interested in the number of people audited in one year. Use a
Poisson distribution to anwer the following questions.
a. In words, define the random variable
b. List the values that may take on.
c. Give the distribution of
d. How many are expected to be audited?
e. Find the probability that no one was audited.
f. Find the probability that at least three were audited.
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