__Exercises for Section 5.1__

- 1.
- According to Horseman's Quarterly, three out of five racehorses lose money.
A racing partnership has 49 horses in its stables.
What is the probability that more than two-thirds of the stable's
horses will lose money?
- 2.
- Suppose that 20% of students in a large university are graduate students.
If a random sample of 125 students are randomly selected,
What is the probability that 25% or more of the sample are
graduate students?
- 3.
- An opinion poll of 800 residents of a large suburb asked whether they
favor a rise
in taxes to help pay for a new shopping mall. If 60% or more support
the tax, a
referendum will be placed on the next election ballot. If the true (population)
proportion of all residents who favor the mall tax is 55%,
what is the probability that a referendum will be placed on the next
ballot? (In other words, what is the probability that the sample
proportion will reach or exceed 60%?)
- 4.
- Eighty percent of small retail businesses experience cash flow problems
during their first
year of operation. A consultant takes a random sample of
60 small businesses that have been in business for one year.
- (a)
- What is the probability that 85% or more of the sampled businesses have experienced cash flow problems?
- (b)
- What is the probability that less than 70% of the sampled businesses have experienced cash flow problems?

- 5.
- Historically, 92% of the overnight deliveries of a parcel service
arrive the next morning
before noon (considered ``on time'' delivery). Suppose 300 deliveries
are randomly selected for the purposes of quality control.
- (a)
- What is the probability that more than 90% of the deliveries were on time?
- (b)
- What is the probability that less than 85% of the deliveries were on time?

__Exercises for Section 5.2__ - 6.
- A random sample of 200 adult Texas residents is taken, and they were asked
whether they approve of the death penalty. Suppose that 80 out of the 200
say they favor the death penalty.
- (a)
- What is estimate of the proportion of adult Texans who favor the death penalty?
- (b)
- Calculate a standard error for your estimate.

- 7.
- A recent poll of 400 Kalamazoo residents resulted in a 60%
approval rating for President Bush.
Calculate a standard error for this estimate.
- 8.
- A sample of 100 individuals showed that 20% experienced gastrointestinal problems
after consuming 10 grams of sorbitol, a common artificial
sweetener.
Attach a standard error to this estimate.