QMB 2100 Business Statistics - Practice Test #2
1. In a binomial distribution where there are 5 trials and the probability of success is 0.40,
what is the variance?
A 0.72
B 1.2
C 1.095
D 1.047
2. In a binomial distribution with an n of 15 and a probability of success of 20 percent, what is
the probability of 10?
A 0.0030
B 0.0020
C 0.0010
D 0.0001
3. In a binomial distribution where there are 5 trials and the probability of success is 0.40,
what is the standard deviation?
A 0.72
B 1.2
C 1.095
D 1.047
4. In order to use a binomial approach to a problem ____ four characteristics of a binomial
must be met.
A all
B some of the
C one of the
D two of the
1
5. In a binomial distribution with an n of 15 and a probability of success of 20 percent, what is
the mean?
A 1.0
B 2.0
C 3.0
D 4.0
6. In a binomial distribution with an n of 15 and a probability of success of 20 percent, what is
the probability of 15 or less?
A 0.00
B 0.50
C 1.00
D 1.50
7. In a binomial distribution the probability of success and failure must remain ________
throughout the total number of trials.
A constant
B mobile
C equal
D infinite
8.
In a binomial distribution the random variable is based upon an experiment that has
________ possible outcomes.
A numerous
B infinity
C two
D one
2
9. In a binomial distribution the result counts the number of ways the ________ variable x
could occur.
A continuous
B random
C bisected
D bimodal
10. The Poisson distribution is:
A symmetrical.
B uniform.
C positively skewed.
D negatively skewed.
11. All normal distribution are symmetrical, bell-shaped, and continuous and theoretically go to
_____ in both directions (asymptotic).
A zero
B one
C ± three
D infinity
12. In a uniform probability distribution with a low point of 6 and a high point of 12, what would
the variance be?
A9
B3
C 18
D 1.73
3
13. The travel times of trains between station A and station B are uniformly distributed with a
low of 15 minutes and a high of 21 minutes. What is the probability of the travel time being
20 minutes or less?
A 0.333
B 0.167
C 0.833
D 0.154
14. The most commonly found continuous distribution is the _______ distribution.
A normal
B uniform
C exponential
D empirical
15. In a uniform probability distribution with a low point of 6 and a high point of 12, what would
the standard deviation be?
A9
B3
C 18
D 1.73
16. If the mean of a normal distribution is 50 and the standard deviation is 5, what is the
probability of between 34 and 42?
A 0.9445
B 0.0007
C 0.0541
D 0.4493
4
17. In a uniform probability distribution with a low point of 6 and a high point of 12, what is the
mean?
A9
B3
C 18
D 1.73
18. The travel times of trains between station A and station B are uniformly distributed with a
low of 15 minutes and a high of 21 minutes. What is the standard deviation of the travel
times?
A 36
B 18
C3
D 1.73
19. A coffee vending machine is programmed to pour 8 ounces of coffee into a cup. According to
the manufacturer’s specifications the population standard deviation of each pour is 0.3
ounces, and the distribution is normal. What is the probability of randomly getting a cup of
coffee and finding it contains more than 9.0 ounces?
A 0.4996
B 0.9996
C 0.0004
D 0.9992
20. A coffee vending machine is programmed to pour 8 ounces of coffee into a cup. According to
the manufacturer’s specifications the population standard deviation of each pour is 0.3
ounces, and the distribution is normal. What is the probability of randomly getting a cup of
coffee and finding it contains between 8.0 and 8.25 ounces?
A 0.2033
B 0.2967
C 0.5934
D 0.7967
5
21. One of the reasons that taking a sample can be a better choice than using the entire
population is:
A the complex nature of experimentation.
B the physical impossibility of getting access to all of the population.
C the confusing nature of samples.
D none of the choices.
22. If a researcher is interested in selecting a sample with the intention of studying a variable
that requires the selection criteria be based upon a demographic issue, the researcher would
be most likely to use a:
A simple random sample.
B systematic random sample.
C stratified random sample.
D cluster random sample.
23. If a researcher was investigating data provided by the 2010 census, examining the dispersion
of incomes within each income category for a specific census tract, the most appropriate
sampling technique to use would be:
A simple random sampling
B systematic random sampling
C stratified sampling.
D cluster sampling.
24. A sample in which every member or element of the population has an equal chance of being
selected from the population is a:
A probability sample.
B non-probability sample.
C random sample.
D convenience sample.
6
25. The denominator for the z for a proportion formula can also be called the:
A standard error of the z.
B standard error of the variance.
C standard error of the mean.
D standard error of the proportion.
26. If the population mean is 1200, the variance is 144, and we have taken samples of 100, what
is the standard error of the mean?
A 1.2
B 12
C 14.4
D 1.44
27. One reason why taking a sample might be a better solution than using the entire population
is the ________ nature of some of the required experiments.
A complex
B confusing
C diffusing
D destructive
28. Two of the key factors that often lead a decision-maker or researcher into gathering a sample
rather than using the entire population, are time and:
A necessity.
B money.
C randomization.
D stratification.
29. A sampling technique that involves multiple stages is a:
A a simple random sample.
B systematic sample.
C stratified sample.
7
D cluster sample.
30. If the mean of the population was 510 and the mean of a sample taken from the population
490, what would the sampling error be?
A 20
B -20
C 1000
D 500
31. If the population standard deviation is unknown we will use the table for a ____ when
obtaining the value for the level of confidence for a confidence interval.
A ? – test
B t - test
C Chi- square test
D proportion
32. A firm can only afford to take a sample survey of 256 people due to budget constraints. If
they use the 95% confidence level and the population standard deviation is 120, what is the
maximum allowed error?
A 0.92
B 10.00
C 14.70
D 20.00
33. There are many commercially available software programs that perform statistical functions.
In many ____ is used as the default setting for the percentage of our level of confidence.
A 90%
B 95%
C 99%
D 99.9%
8
34. In a particular study the N = 10000 n = 250 the sample mean is 275 and the population
standard deviation is 25. Using the 92% confidence level what is the confidence interval
within which the population mean would fall?
A 272.233 to 277.767
B 272.268 to 277.732
C 270.921 to 279.079
D 270.972 to 279.028
35. It is important to understand whether we are working with a mean or a ___ when solving a
confidence interval.
A ? – test
B t - test
C Chi- square test
D proportion
36. In a particular study the N = 10000 n = 500 the sample mean is 275 and the population
standard deviation is 25. Using the 99% confidence level what is the confidence interval
within which the population mean would fall?
A 272.1884 to 277.8116
B 272.1155 to 277.8845
C 272.8640 to 277.136
D 272.8087 to 277.1913
37. A local coffee shop has 5000 total customers, they surveyed 500 customers and found that
60 found their menu offerings to be too restrictive. If we use the 80% confidence level, what
is the confidence interval within which the population proportion lies?
A .1024 to .1376
B .0972 to .1428
C .0930 to .1470
D .0844 to .1556
9
38. As the confidence level goes higher the size of the minimum sample size required goes:
A up.
B down.
C stays the same.
D could go up or down.
39. The E used in the calculation of minimum sample size, represents:
A the value as being an estimate.
B the expected value.
C the interval estimate.
D The maximum margin of error.
40. In a population the standard deviation is 10 and the maximum allowable error is 5. If we use
the 90% confidence level what is the minimum acceptable sample size for a full research
study?
A7
B 11
C 16
D 27
10
ANSWER KEY
1B
2D
3C
4A
5C
6C
7A
8C
9B
10 C
11 D
12 B
13 C
14 A
15 D
16 C
17 A
18 D
19 C
20 B
21 B
22 C
23 C
24 C
25 D
26 A
27 D
28 B
29 D
11
30 B
31 B
32 C
33 B
34 A
35 D
36 A
37 A
38 A
39 D
40 B
12