Bayes’ theorem is used to calculate a subjective probability.
A population is a collection of all individuals, objects, or measurements of interest.
The alternate hypothesis states that the correlation between two populations is greater
than zero. The test of significance is one-tailed.
A dot plot is useful for quickly graphing frequencies in a small data set.
In acceptance sampling, there is one unique operating characteristic curve for a
specified sampling plan.
One of the major U.S. tire makers wishes to review its warranty for their rainmaker tire.
The warranty is for 40,000 miles. The distribution of tire wear is normally distributed
with a population standard deviation of 15,000 miles. The tire company believes that
the tire actually lasts more than 40,000 miles. A sample of 49 tires revealed that the
mean number of miles is 45,000 miles. If we test the hypothesis with a 0.05
significance level, what is the probability of a Type II error if the actual
The shape of the chi-square distribution depends on the number of degrees of freedom.
The following are examples of attributes: the width of a cracked weld, the length of
time that a relay works; the amount of water in a radiator; the diameter of a tire.
A purchasing agent for a trucking company is shopping for replacement tires for their
trucks from two suppliers. The suppliers’ prices are the same. However, Supplier A’s
tires have an average life of 60,000 miles with a standard deviation of 10,000 miles.
Supplier B’s tires have an average life of 60,000 miles with a standard deviation of
2,000 miles.
Which of the following statements is TRUE?
A. The two distributions of tire life are the same.
B. On average, Supplier A’s tires have a longer life than Supplier B’s tires.
C. The life of Supplier B’s tire is more predictable than the life of Supplier A’s tires.
D. The dispersion of Supplier A’s tire life is less than the dispersion of Supplier B’s tire
life.
A set of ordinal-, interval-, or ratio-level data may only have one mode.
What is the logarithmic transformation for the equation Ŷ = a + bt?
A. log a = S log Ŷ/n
B. log Ŷ = log a + log b(t)
C. log b = S(X log) Ŷ/t2
D. Ŷ = abt
ANOVA is a statistical approach used to determine whether or not _________.
A. the means of two or more samples are equal
B. the means of two samples are equal
C. the means of two or more populations are equal
D. the means of more than two samples are equal
A survey of an urban university (population of 25,450) showed that 750 of 1,100
students sampled attended a home football game during the season. Using the 99%
level of confidence, what is the confidence interval for the proportion of students
attending a football game?
A. [0.7671, 0.8143]
B. [0.6550, 0.7050]
C. [0.6464, 0.7172]
D. [0.6805, 0.6815]
The national sales manager for “I colored this” (ICT) T-shirts provides all salespersons
with the following opportunity loss table showing the potential lost profit for each
purchase decision or act from one to four dozen T-shirts. The probability of demand for
each state of nature is also shown.
What is the expected opportunity loss of purchasing two dozen T-shirts?
A. 84
B. 108
C. 156
D. 204
We test for a hypothesized difference between two population means: H0: μ1 = μ2.
The population standard deviations are unknown but assumed equal. The number of
observations in the first sample is 15, and 12 in the second sample. How many degrees
of freedom are associated with the critical value?
A. 24
B. 25
C. 26
D. 27
Random samples of four items are selected from a manufacturing process at regular
intervals and a certain quality characteristic is measured. After 25 samples, ΣX =
15,350 and ΣR = 411.4. To construct a mean chart, what is the value for R bar used to
compute the limits?
A. 411.4
B. 614
C. 16.46
D. 102.88
A manufacturer wants to increase the shelf life of a line of cake mixes. Past records
indicate that the average shelf life of the mix is 216 days. After a revised mix has been
developed, a sample of nine boxes of cake mix gave these shelf lives (in days): 215,
217, 218, 219, 216, 217, 217, 218, and 218. Using α = 0.025, has the shelf life of the
cake mix increased?
A. Yes, because computed t is greater than the critical value.
B. Yes, because computed t is less than the critical value.
C. No, because computed t lies in the region of acceptance.
D. No, because 217.24 is quite close to 216.
The college of business was interested in comparing the attendance for three different
class times for a business statistics class. The data follow.
What are the block and treatment degrees of freedom?
A. 5 and 3
B. 5 and 5
C. 4 and 2
D. 3 and 15
A frequency distribution has a mean of 100 and a standard deviation of 20. The class
limits for one class are 50 up to 60. What are the standard normal z-statistics for the
class limits?
A. -20 and 20
B. -2.5 and -2.0
C. 2.0 and 2.5
D. -50 and -40
A random sample of 20 items is selected from a population. When computing a
confidence interval for the population mean, what number of degrees of freedom should
be used to determine the appropriate t-value?
A. 20
B. 19
C. 21
D. 25
A sales manager for an advertising agency believes that there is a relationship between
the number of contacts that a salesperson makes and the amount of sales dollars earned.
A regression ANOVA shows the following results:
What is the value of the coefficient of correlation?
A. +0.6317
B. +0.9754
C. -0.9754
D. +0.9513
A recent study focused on the number of times men and women send a Twitter message
in a day. The information is summarized next.
At the .01 significance level, is there a difference in the mean number of times men and
women send a Twitter message in a day? What is the value of the test statistic for this
hypothesis test?
A. 2.668
B. 2.672
C. 2.58
D. 2.40
The upper and lower control limits are usually set:
A. at the mean.
B. above the mean.
C. at three standard deviations from the mean.
D. at two standard deviations from the mean.
A research firm needs to estimate within 3% the proportion of junior executives leaving
large manufacturing companies within three years. A 0.95 degree of confidence is to be
used. Several years ago, a study revealed that 21% of junior executives left their
company within three years. To update this study, how many junior executives should
be surveyed?
A. 594
B. 612
C. 709
D. 897
For the third quarter, the sales are 1,500 units; the seasonal index for the quarter is 1.15.
What are the deseasonalized sales for the quarter?
A. 115%
B. 15%
C. 1,304
D. 1,500
Which of the following components is not present in a time series?
A. secular trend
B. regular variation
C. cyclical variation
D. seasonal variation
The variance of a sample of 121 observations equals 441. The standard deviation of the
sample equals
A. 11.
B. 21.
C. 1.91.
D. 231.
An ANOVA procedure is applied to data obtained from four distinct populations. The
samples, each comprised of 15 observations, were taken from the four populations. The
degrees of freedom for the numerator and denominator for the critical value of F are:
A. 4 and 60, respectively.
B. 4 and 21, respectively.
C. 3 and 59, respectively.
D. 3 and 56, respectively.
A tennis match requires that a player win three of five sets to win the match. If a player
wins the first two sets, what is the probability that the player wins the match, assuming
that each player is equally likely to win each set?
A. 0.500
B. 0.125
C. 0.875
D. 0.000
To test a hypothesis that a frequency distribution for sample data is normally
distributed, class limits are transformed using a ____________.
You have a decision to invest $10,000 in any of four different companies. You estimate
the probabilities that the economy will be favorable or unfavorable, and you estimate
the percent returns over the next year.
What is the expected value for Company 1?
The following frequency distribution shows the distribution of delivery times (in days)
for swimstuff.com customer orders during the last month.
What is the relative frequency of the orders delivered from 1 day up to 3 days?
A _____ chart is useful for displaying a frequency distribution for a qualitative variable.
LongLast Inc. produces car batteries. The mean life of these batteries is 60 months. The
distribution of the battery life closely follows the normal probability distribution with a
standard deviation of eight months. As part of its testing program, LongLast tests a
sample of 25 batteries. What is the standard error of the mean?
Data for selected fruits purchased at wholesale prices for 2005 and 2009 are shown
next.
What is the simple price relative for bananas?
When can a paired t-test be used to test a hypothesis of no difference between
population means?
To verify that a frequency distribution for sample data is normally distributed, the
expected frequencies are computed using probabilities from a _____________
distribution.
The human resources department of a software company encourages their employees to
participate in a wellness program. They sampled 16 employees, 2 males and 2 females
from four different workout routines and measured their peak heart rate. The ANOVA
for the research follows.
What is the Interaction sum of squares?
What is the purpose of using a blocking variable in a two-way ANOVA?