If = .0139 and 25 shipments of 20 items each were examined, what are the UCL and
the LCL for the p chart?
A. [.0118, .0159]
B. [0, .0401]
C. [.008, .0198]
D. [0, .0924]
Joe is considering pursuing an MBA degree. He has applied to two different
universities. The acceptance rate for applicants with similar qualifications is 25 percent
for University A and 40 percent for University B.
What is the probability that Joe will be accepted at both universities?
A. 0.10
B. 0.25
C. 0.65
D. 0.625
E. 0.40
A real estate company is analyzing the selling prices of residential homes in a given
community. 140 homes that have been sold in the past month are randomly selected and
their selling prices are recorded. The statistician working on the project has stated that
in order to perform various statistical tests, the data must be distributed according to a
normal distribution. In order to determine whether the selling prices of homes included
in the random sample are normally distributed, the statistician divides the data into 6
classes of equal size and records the number of observations in each class. She then
performs a chi-square goodness-of-fit test for normal distribution. The results are
summarized in the following table
What are the degrees of freedom for the chi-square test?
A. 2
B. 3
C. 4
D. 5
E. 6
If P(A∩B ) = .3 and P(A|B) = .9, find P(B).
A. 0.6
B. 0.3
C. 0.5
D. 0.27
E. 0.33
In a simple linear regression model, the intercept term is the mean value of y when x
equals _____.
A. 1
B. 0
C. −1
D. y
When using simple exponential smoothing, the value of the smoothing constant α
cannot be
A. negative.
B. greater than zero.
C. greater than 1.
D. .99.
E. negative or greater than 1.
A(n) _____________ variable is a qualitative variable such that there is no meaningful
ordering or ranking of the categories.
A. ratio
B. ordinal
C. nominative
D. interval
Two independent samples selected from two normally distributed populations have
variances of σ12 and σ22 with n1 = 10 and n2 = 15. The degrees of freedom for the F
distribution when testing the equality of the two population variances are
A. 10 and 15.
B. 11 and 16.
C. 9 and 14.
D. 8 and 13.
If there are 30 values in a data set, how many classes should be created for a frequency
histogram?
A. 4
B. 5
C. 6
D. 7
E. 8
Last year, TV station KAAA had a share of the 6 p.m. news audience approximately
equal to, but not greater than, 25 percent. The advertising department for the station
believes the current audience share is higher than the 25 percent share they had last
year. In an attempt to substantiate this belief, the station surveyed a random sample of
400 viewers of 6 p.m. news and found that 146 watched KAAA. Calculate the
appropriate test statistic to test the hypotheses using the critical value rule.
The signed ranks test is the nonparametric counterpart of the
A. small-sample t test about a single population mean.
B. two independent samples t test.
C. one-way ANOVA F test.
D. paired difference t test.
E. F test for equality of population variances.
In testing the difference between two means from two normally distributed independent
populations, the distribution of the difference in sample means will be
A. normally distributed only if sample sizes are equal.
B. normally distributed only if both population standard deviations are known.
C. normally distributed.
D. normally distributed if both sample sizes are very large.
E. normally distributed only if both population variances are equal.
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 between 15 and 45 minutes?
A. 1.00
B. .9699
C. .5000
D. .9398
Different levels of a factor are called ____________.
A. treatments
B. variables
C. responses
D. observations
If the errors produced by a forecasting method for 3 observations are −1, −2, and −6,
then what is the mean squared error (deviation)?
A. 9
B. −9
C. 3
D. 13.67
Employees of a local university have been classified according to gender and job type.
If an employee is selected at random, what is the probability that the employee is
female or works as an hourly staff member?
A. 0.133
B. 0.533
C. 0.667
D. 0.400
E. 0.333
As the sample size ______________, the variation of the sampling distribution of
___________.
A. decreases, decreases
B. increases, remains the same
C. decreases, remains the same
D. increases, decreases
E. None of the other choices is correct.
When developing a frequency distribution, the class (group) intervals should be
___________.
A. large
B. small
C. integer
D. mutually exclusive
E. equal
The ______________ is a quantity that measures the variation of a population or
sample relative to its mean.
A. mean
B. standard deviation
C. range
D. coefficient of variation
E. Z-score
Two percent of the customers of a store buy cigars. Half of the customers who buy
cigars buy beer. 25 percent who buy beer buy cigars. Determine the probability that a
customer neither buys beer nor buys cigars.
A. 0.98
B. 0.95
C. 0.75
D. 0.96
E. 0.50
A new company is in the process of evaluating its customer service. The company
offers two types of sales: (1) Internet sales and (2) store sales. The marketing research
manager believes that the Internet sales are more than 10 percent higher than store
sales. The null hypothesis would be
A. PInternet − Pstore > .10.
B. PInternet − Pstore < .10.
C. PInternet − Pstore .10.
D. PInternet − Pstore .10.
E. PInternet − Pstore = .10.
In testing the difference between the means of two normally distributed populations, if
μ1 = μ2 = 50, n1 = 9, and n2 = 13, the degrees of freedom for the t statistic equals
___________.
A. 22
B. 21
C. 19
D. 20
If the Durbin-Watson statistic is less than dL, then we conclude that
A. there is significant positive autocorrelation.
B. there is significant negative autocorrelation.
C. there is significant autocorrelation, but we cannot identify whether it is positive or
negative.
D. the test results are inconclusive.
Which of the following time series forecasting methods would not be used to forecast
seasonal data?
A. dummy variable regression
B. simple exponential smoothing
C. time series decomposition
D. multiplicative Winters method
The internal auditing staff of a local manufacturing company performs a sample audit
each quarter to estimate the proportion of accounts that are more than 90 days overdue
(delinquent). The historical records of the company show that over the past 8 years, the
average has been that 14 percent of the accounts have been delinquent. For this quarter,
the auditing staff randomly selected 250 customer accounts. What is the probability that
at least 30 accounts will be classified as delinquent?
A. 31.86%
B. 18.14%
C. 81.86%
D. 63.72%
E. 75.84%
A major drawback of the aggregate price index is that
A. it does not take into account the fact that some items in the market basket are
purchased more frequently than others.
B. it is difficult to compute.
C. it is computed by using the values from a single time series or based on a single
product.
D. percentage comparisons cannot be made to the base year.
An experiment in which two different measurements are taken on the same units and
inferences are made using the differences between the pairs of measurements is a(n)
______ experiment.
A. paired difference
B. equal variances
C. independent samples
D. dependent samples
When we carry out a chi-square test of independence, as the differences between the
respective observed and expected frequencies decrease, the probability of concluding
that the row variable is independent of the column variable
A. decreases.
B. increases.
C. may decrease or increase depending on the number of rows and columns.
D. will be unaffected.
The multiple _________ measures the proportion of the variation in y (response
variable) explained by the multiple regression model or the set of independent variables
included in the multiple regression equation.
A. correlation coefficient
B. coefficient of determination
C. total variation
D. standard error
E. F test
A(n) _______ chart monitors the number of nonconforming units in a subgroup.
A.
B. R
C. C
D. p
Consider the following data.
Using simple exponential smoothing with α = 0.2, determine the forecast error for time
period 1.
A local real estate agent claims that the median selling price of homes in a major
midwestern city is more than $200,000. Suppose a random sample of 100 homes sold in
the last six months is taken and 53 sold for over $200,000. Using α = .01, test the real
estate agent’s claim. What do you conclude about the selling prices of the homes?
A. Reject the null hypothesis.
B. Do not reject the null hypothesis.
Suppose you are a researcher investigating the annual sales differences among five
categories of businesses. The study looks at 55 companies equally divided among
categories A, B, C, D, and E.
Source SS DF MS F
Treatment 583.39 4 145.85 7.501
Error 972.18 50 19.4436
Total 1555.57 54
Is there a significant difference in the annual sales of the five business categories at α
= .05? Do you reject H0 ?
A real estate appraiser is gathering housing sales data by street in the neighborhood in
preparation for his next job. Listed below are the six streets and the average sales price
and the houses sold in the last 12 months. Calculate the mean sales price for the
neighborhood.
Given the following data, compute the mean absolute deviation.
In a study of distances traveled by buses before the first major engine failure, a sample
of 191 buses results in a mean of 96,700 miles and a population standard deviation of
37,500 miles. Calculate the p-value corresponding to the test statistic used to test the
claim that the mean distance traveled before a major engine failure is more than 90,000
miles and, applying the p-value rule, determine if the null hypothesis can be rejected at
α = .01.
The quality control manager for NKA Inc. must decide whether to accept (alternative
1), further analyze (alternative 2), or reject (alternative 3) an incoming shipment (lot) of
microchips. The historical data indicate that there is a 30 percent chance that the lot is
poor quality (S1), 50 percent chance that the lot is fair quality (S2), and 20 percent
chance that the lot is good quality (S3). Assume the following payoff table is available.
The values in the payoff table are in thousands of dollars.
What alternative action should be selected according to the maximax criterion?
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 for the
treatments?
Use the following price information for three grains.
Calculate the simple price index for each grain separately.
A fast food company uses two management-training methods. Method 1 is a traditional
method of training, and Method 2 is a new and innovative method. The company has
just hired 31 new management trainees. 15 of the trainees are randomly selected and
assigned to the first method, and the remaining 16 trainees are assigned to the second
training method. After three months of training, the management trainees take a
standardized test. The test was designed to evaluate their performance and learning
from training. The sample mean score and sample standard deviation of the two
methods are given below. The management wants to determine if the company should
implement the new training method.
What is the sample value of the test statistic?
Consider an engine parts supplier, and suppose the supplier has determined that the
mean and variance of the population of all cylindrical engine part outside diameters
produced by the current machine are, respectively, 2.5 inches and .00075. To reduce this
variance, a new machine is designed. A random sample of 20 outside diameters
produced by this new machine has a sample mean of 2.5 inches and a variance of s2 = .
0002 (normal distribution). In order for a cylindrical engine part to give an engine long
life, the outside diameter must be between 2.43 and 2.57 inches. If σ2 denotes the
variance of the population of all outside diameters that would be produced by the new
machine, test H0: σ2 = .00075 versus Ha: σ2 < .00075 by setting α = .05.
When we test H0: μ1 − μ2 0, HA: μ1 − μ2> 0, = 15.4, = 14.5, σ1 = 2, σ2 = 2.28,
n1 = 35, and n2 = 18 at α = .01, what is the value of the test statistic?
A local tire dealer wants to predict the number of tires sold each month. He believes
that the number of tires sold is a linear function of the amount of money invested in
advertising. He randomly selects 6 months of data consisting of monthly tire sales (in
thousands of tires) and monthly advertising expenditures (in thousands of dollars). The
simple linear regression equation is ŷ = 3 + 1x, and the sample correlation coefficient
(r2) = .6364. Test to determine if there is a significant correlation between the monthly
tire sales and monthly advertising expenditures. Use H0: ρ = 0 vs. HA: ρ ≠ 0 at α = .05.
On the most recent tax cut proposal, a random sample of Democrats and Republicans in
the Congress cast their votes as follows.
Suppose that the chi-square test of independence is performed and the null hypothesis
(the vote on the issue and party affiliation are independent) is rejected. Provide a
one-sentence interpretation of the outcome of the test.
Two forecasting models were used to predict the future values of a time series. The
forecasts are shown below with the actual values.
Calculate the mean absolute deviation (MAD) for Model 1.
