A fair die is rolled 10 times. What is the probability that an even number (2, 4, or 6) will
occur between 2 and 4 times?
A. .6123
B. .1709
C. .1611
D. .3662
E. .3223
When the data being studied are gathered from a published source, this is referred to as
a(n) _______________.
A. existing data source
B. observational data source
C. experimental data source
D. cross-sectional data source
A sample of 2,000 people yielded =.52. What is the variance of the population
proportion?
A. .0056
B. .0112
C. .00012
D. .0161
Of all individual tax returns, 37 percent include errors made by the taxpayer. If IRS
examiners are assigned randomly selected returns in batches of 12, find the mean and
standard deviation for the number of erroneous returns per batch.
A. μ = 2.80, σ = 1.67
B. μ = 4.44, σ = 1.67
C. μ = 4.44, σ = 2.80
D. μ = 7.56, σ = 2.80
_____________ occurs when some population elements are excluded from the process
of selecting the sample.
A. Non-response
B. Error of observation
C. Undercoverage
D. Sampling error
In performing a chi-square test of independence, as the differences between respective
observed and expected frequencies _________, the probability of concluding that the
row variable is independent of the column variable increases.
A. stay the same
B. decrease
C. increase
D. double
If the decision maker has no knowledge about the likelihood of any of the states of
nature occurring, then it can be stated that the decision maker is operating in an
environment of
A. certainty.
B. uncertainty.
C. risk.
D. optimism.
Suppose that the waiting time for a license plate renewal at a local office of a state
motor vehicle department has been found to be normally distributed with a mean of 30
minutes and a standard deviation of 8 minutes. What is the probability that a randomly
selected individual will have a waiting time of no more than 22 minutes?
A. .1587
B. .9977
C. .8413
D. .0023
The basic difference between MAD and MSE is that MSE, unlike MAD, penalizes a
forecasting technique much more for _________ errors than for _________ errors.
A. large, small
B. small, large
C. small, zero
D. zero, large
A null hypothesis is not rejected at a given level of significance. As the assumed value
of the mean gets further away from the true population mean, the Type II error will
_____________.
A. increase
B. decrease
C. stay the same
D. randomly fluctuate
In simple regression analysis, if the correlation coefficient is a positive value, then
A. the y-intercept must also be a positive value.
B. the coefficient of determination can be either positive or negative, depending on the
value of the slope.
C. the least squares regression equation could have either a positive or a negative slope.
D. the slope of the regression line must also be positive.
E. the standard error of estimate can have either a positive or a negative value.
What is a 95 percent confidence interval for μ when n = 10, =35.6, and s = 13.0?
Assume population normality.
A. [26.44, 44.76]
B. [26.30, 44.90]
C. [33.02, 38.18]
D. [27.54, 43.66]
At the end of their final exam, 550 students answered an additional question in which
they rated their instructor’s teaching effectiveness, with the following results.
What proportion of the students who rated their instructor as very or somewhat
effective received a B or better in the class?
A. 0.03
B. 0.06
C. 0.08
D. 0.13
E. 0.15
In a major midwestern university, 55 percent of all undergraduates are female, 25
percent of all undergraduates belong to a Greek organization (fraternity or sorority), and
40 percent of all males belong to a Greek organization. What percentage of the
undergraduates are female and in a Greek organization?
A. 55%
B. 25%
C. 60%
D. 7%
E. 15%
According to a survey of the top 10 employers in a major city in the Midwest, a worker
spends an average of 413 minutes a day on the job. Suppose the standard deviation is
26.8 minutes, and the time spent is approximately a normal distribution.
What are the times within which approximately 68.26 percent of all workers will fall?
A. [394.8, 431.2]
B. [386.2, 439.8]
C. [372.8, 453.2]
D. [359.4, 466.6]
E. [332.6, 493.4]
A person’s telephone area code is an example of a(n) _____________ variable.
A. nominative
B. ordinal
C. interval
D. ratio
A manufacturing company produces part QV2Y for the aerospace industry. This
particular part can be manufactured using 3 different production processes. The
management wants to know if the quality of the units of part QV2Y is the same for all
three processes. The production supervisor obtained the following data: Process 1 had
29 defective units in 240 items, Process 2 produced 12 defective units in 180 items, and
Process 3 manufactured 9 defective units in 150 items. At a significance level of .05, we
performed a chi-square test of independence to determine if the quality of the items
produced appears to be independent of the production process. What are the degrees of
freedom for the chi-square statistic?
A. 2
B. 3
C. 50
D. 520
E. 570
A foreman wants to use an chart to control the average length of the bolts
manufactured. He has recently collected the six samples given below.
Sample
1 1.99 2.01 2.02 2.02
2 2.00 2.00 2.01 2.01
3 1.98 1.99 2.01 1.98
4 2.01 2.02 2.02 1.99
5 1.99 1.99 2.01 1.99
6 2.03 1.98 2.03 2.04
Calculate the average range.
A. .036
B. .18
C. .030
D. .05
822 customers were randomly selected from those who had recently bought a book over
the Internet. The chart below shows the breakdown of the classification of the book
type.
What percentage of the books were in the top two categories?
A. 22.99
B. 20.44
C. 4.50
D. 43.43
E. 0.4343
The χ2 statistic from a contingency table with 6 rows and 5 columns will have
A. 30 degrees of freedom.
B. 24 degrees of freedom.
C. 5 degrees of freedom.
D. 20 degrees of freedom.
E. 25 degrees of freedom.
A motorcycle manufacturer produces the parts for its vehicles in different locations and
transports them to its plant for assembly. In order to keep the assembly operations
running efficiently, it is vital that all parts be within specification limits. One important
part used in the assembly is the engine camshaft, and one important quality
characteristic is the case hardness depth. Specifications state that the hardness depth
must be between 3.0 mm and 6.0 mm. To investigate the process, the quality control
engineer selected 25 daily subgroups of n = 5 and measured the hardness depth. The
process yielded a mean of the means = 4.50 and an average range = 1.01. Calculate the
center line for the R chart.
A. 1.01
B. 0.22
C. 4.50
D. 0.90
In a completely randomized (one-way) analysis of variance problem with c groups and
a total of n observations in all groups, the variance between groups is equal to
A. (Total sum of squares) − (Sum of squares within columns).
B. (Sum of squares between columns)/(c − 1).
C. (Total sum of squares) − [(Sum of squares within columns)/(n − c)].
D. [(Total sum of squares)/(n − 1)] − [(Sum of squares between columns)/(c − 1)].
Which of the following graphs is for qualitative data?
A. histogram
B. bar chart
C. ogive plot
D. stem-and-leaf
The number of miles a truck is driven before it is overhauled is an example of a(n)
_____________ variable.
A. nominative
B. ordinal
C. interval
D. ratio
During off hours, cars arrive at a tollbooth on the East-West toll road at an average rate
of 0.5 cars per minute. The arrivals are distributed according to a Poisson distribution.
What is the probability that during the next minute, three cars will arrive?
A. .0758
B. .1255
C. .0126
D. .0613
The state agriculture department tested 203 fuel samples across the state in 2009 for
accuracy of the reported octane level. For premium grade, 14 out of 105 samples failed.
How many samples would be needed to create a 99 percent confidence interval that is
within 0.02 of the true proportion of premium grade fuel-quality failures?
A. 4148
B. 2838
C. 1913
D. 744
E. 54
If a multiple regression model has a(n) ____________ statistic substantially greater
than k + 1, then it can be shown that this model has substantial bias and is undesirable.
A. C
B. F
C. Cook’s distance
D. Durbin-Watson
Use this information about 10 shipments of lightbulbs.
Shipment 1 2 3 4 5 6 7 8 9 10
# of defective units 0 1 2 0 4 3 2 1 3 4
If 400 bulbs are selected at random from each of 10 shipments and the number of
defectives in each shipment is given above, find the appropriate center line.
A. .005
B. .05
C. .0025
D. .01
There is an average of 22.455 employees at 22 office furniture dealers in a major
metropolitan area, with a standard deviation of 18.52. Construct a 99 percent
confidence interval for the true mean number of full-time employees at office furniture
dealers.
A. [11.014, 33.896]
B. [11.275, 33.635]
C. [12.284, 32.626]
D. [12.513, 32.397]
E. [20.072, 24.838]
The expected net gain of sampling equals the expected ______________ minus the cost
of sampling.
A. payoff of sampling
B. payoff of no sampling
C. value of sample information
D. value of perfect information
E. utility
A motorcycle manufacturer produces the parts for its vehicles in different locations and
transports them to its plant for assembly. To keep the assembly operations running
efficiently, it is vital that all parts be within specification limits. One important part used
in the assembly is the engine camshaft, and one important quality characteristic is the
case hardness depth. Specifications state that the hardness depth must be between 3.0
mm and 6.0 mm. To investigate the process, the quality control engineer selected 25
daily subgroups of n = 5 and measured the hardness depth. The process yielded a mean
of the means = 4.50 and an average range = 1.01. Calculate the control limits for the R
chart.
A. [.464, 1.556]
B. [0, 2.349]
C. [0, 2.114]
D. [0, 2.135]
The weight of a product is normally distributed with a standard deviation of .5 ounces.
What should the average weight be if the production manager wants no more than 5
percent of the products to weigh more than 5.1 ounces?
A. 4.278
B. 4.409
C. 3.455
D. 5.922
A test of driving ability is given to a random sample of 10 student drivers before and
after they complete a formal driver education course. Results follow.
Calculate the mean difference between the before-class scores and the after-class
scores.
Determine the p-value for H0: p ≤ .5; versus HA: p > .5, when n = 225 and = .54.
Consider a standard deck of 52 playing cards, a randomly selected card from the deck,
and the following events: R = red, B = black, A = ace, N = nine, D = diamond, and C =
club.
Are R and A mutually exclusive?
A. Yes, mutually exclusive.
B. No, not mutually exclusive.
The following data on prices and quantities for the years 1995 and 2000 are given for
three products.
Calculate the 2000 aggregate price index.
Sample 1 has data: 16, 14, 19, 18, 19, 20, 15, 18, 17, 18; and sample 2 has data: 13, 19,
14, 17, 21, 14, 15, 10, 13, 15. Testing the equality of means at α = .05, can we reject the
null hypothesis (using critical value rules)?
A local electronics retailer recently conducted a study on purchasers of large screen
televisions. The study recorded the type of television and the credit account balance of
the customer at the time of purchase. They obtained the following results.
Construct a table of column percentages.
The following data consist of the number of sick days taken by the 100 employees at a
small manufacturing company for the past 18 months. Construct a dot plot of these data
and describe the distribution.
5, 1, 4, 8, 0, 6, 3, 5, 3, 4, 7, 15, 5, 8, 2, 1, 5, 4
At the end of 2007, the IRA owned by Joe Smith had a value of $1.2 million. With a
rate of return of −29.75 percent in 2008 and a rate of return of 2.98 percent in 2009,
calculate the geometric mean rate of return for the two-year period.
Looking at four different diets, a researcher randomly assigned 20 equally overweight
individuals into each of the four diets. What are the degrees of freedom total?
Find a 99 percent confidence interval for the difference between means, given that n1 =
49, n2 = 49, = 87, = 92, s12 = 13, and s22 = 15. (Assume unequal variances.)
A coffee shop franchise owner is looking at two possible locations for a new shop. To
help make a decision, he looks at the number of pedestrians that go by each of the two
locations in one-hour segments. At location A, counts are taken for 35 one-hour units,
with a mean number of pedestrians of 421 and a sample standard deviation of 122. At
the second location (B), counts are taken for 50 one-hour units, with a mean number of
pedestrians of 347 and a sample standard deviation of 85. Assume the two population
variances are not known but are equal. Calculate the pooled estimate of σ2.
On the most recent tax cut proposal, a random sample of Democrats and Republicans in
the Congress cast their votes as follows.
Calculate the chi-square statistic for this test of independence.
The number of weekly sales calls by a sample of 25 pharmaceutical salespersons is
below.
24, 56, 43, 35, 37, 27, 29, 44, 34, 28, 33, 28, 46, 31, 38, 41, 48, 38, 27, 29, 37, 33, 31,
40, 50
Construct a stem-and-leaf plot.
Find a 90 percent confidence interval for the difference between the proportions of
failures in factory 1 and factory 2, where 1 = .05, 2 = .04, n1 = 500, and n2 = 2000.