This document provides a guide for a final exam in QNT 561 that includes 30 multiple choice questions covering topics in statistics including confidence intervals, hypothesis testing, probability distributions, and sampling. The questions assess understanding of concepts like means, standard deviations, the central limit theorem, confidence intervals, hypothesis testing, and sampling distributions.

1. QNT 561 Final Exam Guide (New, 2017)
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1. James Desreumaux, VP of Human Resources of American First Banks (AFB), is
reviewing the employee training programs of AFB banks. His staff randomly selected
personnel files for 100 tellers in the Southeast Region and determined that their mean
training time was 25 hours. Assume that the population standard deviation is 5 hours.
The 95% confidence interval for the population mean of training times is
2. If x is a binomial random variable with n=10 and p=0.8, the mean value
of x is______
3. According to the central limit theorem, for samples of size 64 drawn from a
population with µ =800 and σ = 56, the standard deviation of the sampling distribution
of sample means would equal ______
4. Life tests performed on a sample of 13 batteries of a new model indicated: (1)
an average life of75 months, and (2) a standard deviation of 5 months. Other battery
models, produced by similar processes, have normally distributed life spans. The 98%
confidence interval for the population mean life of the new model is _________
5. A large national company is considering negotiating cellular phone rates for its
employees Human Resource department would like to estimate the proportion of its
employee population who own an Apple iPhone. A random sample of size 250 is
taken and 40% of the sample own and iPhone.. The 95% confidence interval to
estimate the population proportion is _______
6. The number of bags arriving on the baggage claim conveyor belt in a 3 minute
time period would best be modeled with the ________
7. The weight of a USB flash drive is 30 grams and is normally distributed.
Periodically, quanlity control inspectors at Dallas Flash Drives randomly select a
sample of 17 USB flash drive. If the mean weight of the USB flash drives is too heavy
or too light the machinery is shut down for adjustment; otherwise, the production
process continues. The last sample showed a meanand standard deviation of 31.9 and
1.8 grams, respectively. Using a = 0.10, theappropriate decision is_______
8. Elwin Osbourne, CIO at GFS, Inc., is studying employee use of GFS e-mail for
non-business communications. He plans to use a 95% confidence interval estimate of
the proportion of e-mail messages that are non-business; he will accept a 0.05 error.
Previous studies indicate that approximately 30% of employee e-mail is not business
related. Elwin should sample _______ e-mail messages

2. 9. The following frequency distribution was constructed for the wait times in the
emergency room The frequency distribution reveals that the wait times in the
emergency room are _______
10. The number of cars arriving at a toll booth in five-minute intervals is Poisson
distributed with a mean of 3 cars arriving in five-minute time intervals. The
probability of 5 cars arriving over a five-minute interval is ________
11. The number of finance majors within the School of Business is an example of
_______
12. According to the central limit theorem, for samples of size 64 drawn from a
population with µ = 800 and σ = 56, the mean of the sampling distribution of sample
means would equal _______
13. Consider the following null and alternative hypotheses Ho: m ≤ 67 Ha: m > 67
These hypotheses ___________
14. A market research team compiled the following discrete probability distribution
on the numberof sodas the average adult drinks each day. In this
distribution, x represents the number of sodas which an adult drinks
x
P(x)
0
0.30
1
0.10
2
0.50
3
0.10
The mean (average) value of x is ______________
15. A researcher wants to determine the sample size necessary to adequately conduct
a study to estimate the population mean to within 5 points. The range of population
values is 80 and the researcher plans to use a 90% level of confidence. The sample
size should be at least ______
16. The mean life of a particular brand of light bulb is 1200 hours. If you know that
at about 95% of this brand of bulbs will last between 1100 and 1300 hours, then what
is the standard deviation of the light bulbs’ life?

3. 17. Completion time (from start to finish) of a building remodeling project is
normally distributed with a mean of 200 work-days and a standard deviation of 10
work-days. To be 99% sure that we will not be late in completing the project, we
should request a completion time of ______ work-day.
18. A large industrial firm allows a discount on any invoice that is paid within 30
days. Of all invoices, 10% receive the discount. In a company audit, 10 invoices are
sampled at random. The probability that fewer than 3 of the 10 sampled invoices
receive the discount is approximately_______________.
19. Suppose a population has a mean of 400 and a standard deviation of 24. If a
random sample of size 144 is drawn from the population, the probability of drawing a
sample with a mean less than 402 is _______
20. If x is a binomial random variable with n=10 and p=0.8, what is the probability
that x is equal to 4 ?
21. The normal distribution is used to test about a population mean for large samples
if the population standard deviation is known. "Large" is usually defined as _______
22. Lucy Baker is analyzing demographic characteristics of two television
programs, Americandol (population 1) and 60 Minutes (population 2). Previous
studies indicate no difference in the ages of the two audiences (The mean age of each
audience is the same.) Lucy plans to test this hypothesis using a random sample of 100
from each audience. Her null hypothesis is
23. Maureen McIlvoy, owner and CEO of a mail order business for wind surfing
equipment and supplies, is reviewing the order filling operations at her warehouses.
Her goal is 100% of orders shipped within 24 hours. In previous years, neither
warehouse has achieved the goal, but the East Coast Warehouse has consistently out-
performed the West Coast Warehouse. Her staff randomly selected 200 orders from
the West Coast Warehouse (population 1) and 400 orders from the East Coast
Warehouse (population 2), and reports that 190 of the West Coast Orders were
shipped within 24 hours, and the East Coast Warehouse shipped 372 orders within 24
hours. Maureen's alternate hypothesis is _______
24. Ophelia O'Brien, VP of Consumer Credit of American First Banks (AFB),
monitors the default rate on personal loans at the AFB member banks. One of her
standards is "no more than 5% of personal loans should be in default." On each
Friday, the default rate is calculated for a sample of 500 personal loans. Last Friday's
sample contained 30 defaulted loans. Ophelia's null hypothesis is _______.
25. Catherine Chao, Director of Marketing Research, is evaluating consumer
acceptance of a new toothpaste package. Her staff reports that 17% of a random
sample of 200 households prefers the new package to all other package designs. If
Catherine concludes that 17% of all households prefer the new package, she is using
_______.

4. 26. The empirical rule says that approximately what percentage of the values would
be within 2 standard deviations of the mean in a bell shaped set of data
27. Medical Wonders is a specialized interior design company focused on healing
artwork. The CEO, Kathleen Kelledy claims that artwork has healing effects for
patients staying in a hospital, as measured by reduced length of stay. Her current client
is a children’s cancer hospital. Kathleen is interested in determining the effect of three
different pieces of healing artwork on children. She chooses three paintings (a horse
photo, a bright abstract, and a muted beach scene) and randomly assigns six hospital
rooms to each painting. Kathleen's null hypothesis is _____________
28. The expected (mean) life of a particular type of light bulb is 1,000 hours with a
standard deviation of 50 hours. The life of this bulb is normally distributed. What is
the probability that a randomly selected bulb would last fewer than 940 hours
29. The mean life of a particular brand of light bulb is 1200 hours and the standard
deviation is 75 hours. Tests show that the life of the bulb is approximately normally
distributed. It can be concluded that approximately 68% of the bulbs will last between
_______.
30. A market researcher is interested in determining the average income for families
in San Mateo County, California. To accomplish this, she takes a random sample of
300 families from the county and uses the data gathered from them to estimate the
average income for families of the entire county. This process is an example of
_______.