When using a completely randomized design (one-way analysis of variance), the
calculated F statistic will decrease as
A. the variability among the groups decreases relative to the variability within the
groups.
B. the total variability increases.
C. the total variability decreases.
D. the variability among the groups increases relative to the variability within the
groups.
At an oceanside nuclear power plant, seawater is used as part of the cooling system.
This raises the temperature of the water that is discharged back into the ocean. The
amount that the water temperature is raised has a uniform distribution over the interval
from 10 to 25 C. What is the probability that the temperature increase will be between
20 and 22 C?
A. 0.08
B. 0.88
C. 0.13
D. 0.20
Statistical ____________ refers to using a sample of measurements and making
generalizations about the important aspects of a population.
A. sampling
B. process
C. analysis
D. inference
For a given multiple regression model with three independent variables, the value of the
adjusted multiple coefficient of determination is_________ less than R2.
A. always
B. sometimes
C. never
In the randomized block ANOVA, the sum of squares for factor 1 equals
A. SSTO − SS(error) − SS(interaction).
B. SSTO − SS(factor 2) − SSE.
C. SSTO − SS(interaction) − SS(factor 2).
D. SSTO − SS(factor 2).
E. SSTO − SS(error).
Health insurers and the federal government are both putting pressure on hospitals to
shorten the average length of stay (LOS) of their patients. In 2003, the average LOS for
non-heart patients was 4.6 days. A random sample of 20 hospitals in one state had a
mean LOS for non-heart patients in 2008 of 3.8 days and a standard deviation of 1.2
days. How large a sample of hospitals would we need to be 99 percent confident that
the sample mean is within 0.5 days of the population mean?
A. 3
B. 7
C. 32
D. 48
E. 96
Temperature (in degrees Fahrenheit) is an example of a(n) __________ variable.
A. nominative
B. ordinal
C. interval
D. ratio
If x is a Poisson random variable with a mean of 10, what is the probability that x is
equal to 8?
A. .1126
B. .1251
C. .2677
D. .0993
Find P( > 172), if μ = 175 and = 9.
A. .1587
B. .8413
C. .6293
D. .3707
When a forecaster uses the ______________ method, she or he assumes that the time
series components are changing slowly over time.
A. time series regression
B. exponential smoothing
C. index number
D. multiplicative decomposition
If the mileage per gallon for a car is normally distributed, 32 mpg has a z score of 1.2,
and 24 mpg has a z score of −.4, what is the mean mpg of the distribution?
A. 28
B. 26
C. 30
D. 38
Determine the probability that a 3 will appear twice, if a single fair die is rolled 10
times.
A. .5010
B. .2907
C. .2318
D. .0065
XYZ Company, Annual Data
Based on the information given in the table above, what is the MAD?
A. 1.3333
B. 1.6667
C. 2.5
D. 3.3333
E. 4.5
Which one of the following nonparametric methods can be used with a single
population?
A. Spearman’s test
B. sign test
C. Kruskal-Wallis test
D. Wilcoxon rank sum test
In a statistics class, 10 scores were randomly selected with the following results: 74, 73,
77, 77, 71, 68, 65, 77, 67, 66.
What is the 65th percentile?
A. 65.5
B. 67.3
C. 66.75
D. 74.0
E. 77.0
A hypergeometric random variable x has a distribution that is approximated by a
binomial distribution when
A. the number of successes is larger than the number of failures in the population.
B. a sample is selected from the population without replacement.
C. the population is much larger than the sample size.
D. the sample size is half the size of the original population.
A golf tournament organizer is attempting to determine whether hole (pin) placement
has a significant impact on the average number of strokes for the 13th hole on a given
golf course. Historically, the pin has been placed in the front right corner of the green,
and the historical mean number of strokes for the hole has been 4.25, with a standard
deviation of 1.6 strokes. On a particular day during the most recent golf tournament, the
organizer placed the hole (pin) in the back left corner of the green. 64 golfers played the
hole with the new placement on that day. Determine the probability of the sample
average number of strokes exceeding 4.75.
A. .9938
B. .4013
C. .0062
D. .3783
Which one of the following graphical tools is used with quantitative data?
A. bar chart
B. histogram
C. pie chart
D. Pareto chart
The Central Limit Theorem states that as the sample size increases, the distribution of
the sample ____________ approaches the normal distribution.
A. medians
B. means
C. standard deviations
D. variances
Find a 98 percent confidence interval for p when = .25 and n = 400.
A. [.206, .294]
B. [.231, .269]
C. [.228, .272]
D. [.200, .300]
A powder metal manufacturing company is producing sleeves for a locking mechanism.
The target (nominal) value for the inside diameter is 1 inch. The inside diameter
specifications are 1 .005 inches. Assume that the process is in statistical control with
= 1.0002 inches, = .003 inches, and subgroup size of 5. What is the sigma level
capability for this process?
A. 3.0
B. 3.72
C. 1.6
D. 1.0
E. 2.72
A cholesterol test was given to ten heart patients with high cholesterol levels. The same
ten heart patients are then given a new cholesterol-reducing drug for six months. Before
the patients begin taking the drug, they are told to maintain their current diets and
eating habits so that the effect of the drug can be more effectively determined. After
taking the drug for six months, the same patients are given a cholesterol test again. The
cholesterol levels before and after taking the drug are given below. The cholesterol level
readings are not normally distributed. At α = .05, test to determine if the drug is helpful
in reducing cholesterol levels.
Cholesterol level
Patient Before After
1 210 205
2 208 204
3 185 186
4 215 207
5 192 193
6 218 214
7 170 178
8 196 190
9 220 212
10 215 204
A. Reject the null hypothesis.
B. Do not reject the null hypothesis.
During the past six months, 73.2 percent of US households purchased sugar. Assume
that these expenditures are approximately normally distributed with a mean of $8.22
and a standard deviation of $1.10. Find the probability that a household spent more than
$10.00 on sugar.
A. .7320
B. .9474
C. .0526
D. .2680
New car owners were asked to evaluate their experiences in buying a new car during
the past 12 months. In the survey, the owners indicated they were most satisfied with
their experiences at the following three dealers (in no particular order): Subaru, Honda,
and Buick. Assuming that each set of rankings is equally likely, what is the probability
that owners ranked Subaru first?
A. 1/3
B. 1/6
C. 1/2
D. 5/6
E. 6/6
In multiple regression analysis, which one of the following is the appropriate notation
for error (residual)?
A.
B.
C.
D.
E. None of these answers is correct.
A research study investigated differences between male and female students. Based on
the study results, we can assume the population mean and standard deviation for the
GPA of male students are = 3.5 and σ = 0.5. Suppose a random sample of 100 male
students is selected and the GPA for each student is calculated. Calculate .
A. 0.5
B. 3.5
C. 7.0
D. 0.05
In a manufacturing process, we are interested in measuring the average length of a
certain type of bolt. Past data indicate that the standard deviation is .25 inches. How
many manufactured bolts should be sampled in order to make us 95 percent confident
that the sample mean bolt length is within .02 inches of the true mean bolt length?
A. 25
B. 49
C. 423
D. 601
E. 1225
The chi-square goodness-of-fit is _________ a one-tailed test with the rejection region
in the right tail.
A. always
B. sometimes
C. never
A random sample of size 1,000 is taken from a population where p = .20. What is ?
A. .006
B. .20
C. .02
D. .16
A corn farmer has categorized the weather into three possible levels. The weather
conditions will affect the timing of the harvest and the associated payoff. In this
situation, the weather conditions are called the ____________________.
A. alternatives
B. states of nature
C. payoffs
D. perfect information
When computing a 95 percent confidence interval for σ2 with a sample of n = 30, what
values of χ2 would we use in the calculations?
A. 45.7222 and 16.0471
B. 46.9792 and 16.7908
C. 42.5569 and 17.7083
D. 43.7729 and 18.4926