In decision making, if there are one or more unknown factors, then the decision is made
under conditions of uncertainty.
When estimating the specific seasonals for a monthly time series, the sum of the 12
modified means should theoretically be equal to 1,200 because the average of the 12
specific seasonals is designated as 100.
The number of children in a family is a discrete variable.
The standard error of estimate measures the accuracy of a prediction.
Statistics are used to report the summary results of market surveys.
One factor in determining the size of a sample is the degree of confidence selected. This
is usually 0.95 or 0.99, but it may be any degree of confidence you specify.
The probability of rolling a 3 or 2 on a single die is an example of mutually exclusive
events.
The purpose of a statistical quality control chart is to identify when assignable causes of
variation have entered the production system so that the cause may be identified and
corrected.
If a confidence interval for the difference between a pair of treatment means includes 0,
then we reject the null hypothesis that there is no difference in the pair of treatment
means.
In frequency distributions, classes are mutually exclusive if each individual, object, or
measurement is included in only one category.
Non-stop Airlines determined that the mean number of passengers per flight is 152 with
a standard deviation of 10 passengers. Practically all flights have between 142 and 162
passengers.
When using stratified random sampling, the sampling error will be zero.
A confidence interval can be determined for the mean value of Y for a given value of X.
A box plot shows the skewness of a distribution.
A scatter diagram is used to illustrate a relationship between gender and the preference
for Coke or Pepsi.
A combination of a set of objects is defined by the order of the objects.
An alternate hypothesis is a statement about a population parameter that is accepted
when the null hypothesis is rejected.
When dependent samples are used to test for differences in the means, we compute
paired differences.
Given the following ANOVA table for three treatments each with six observations:
What is the decision regarding the null hypothesis?
A. Reject H0‘”there is a difference in treatment means.
B. Fail to reject H0‘”there is a difference in treatment means.
C. Reject H0‘”there is a difference in errors.
D. Fail to reject H0‘”there is a difference in errors.
Using a 5% level of significance and a sample size of 25, what is the critical t value for
a null hypothesis, H0: ≤ 100?
A. 1.708
B. 1.711
C. 2.060
D. 2.064
Consider a situation where the lower control limit of a percent defective chart is
negative. It must be that:
A. the absolute value of the negative LCL must be taken to arrive at a positive value.
B. an error was made in computing the LCL because negative values are impossible.
C. the process is out of control and must be redesigned.
D. the lower limit is set to zero.
The Quality Assurance Department selected 12 samples of 100 printed circuit boards
and tested them. The number of defective printed circuit boards in each sample was 3,
3, 0, 5, 1, 1, 5, 6, 6, 2, 0, and 1. What kind of control chart should be constructed to
monitor the process?
A. mean chart
B. range chart
C. percent defective chart
D. c-bar chart
A company is researching the effectiveness of a new website design to decrease the
time to access a website. Five website users were randomly selected, and their times (in
seconds) to access the website with the old and new designs were recorded. To compare
the times, they computed (new website design time – old website design time). The
results follow.
What is the alternative hypothesis?
A. H1: d = 0
B. H1: d ≠0
C. H1: d > 0
D. H1: d < 0
For the trend equation, log Ŷ = log (a) + log (bt), the time series is _____.
A person is trying to decide if they should buy a lottery ticket. The ticket costs $2.00. If
the ticket is a winner, the prize would be $1,000. Knowing that winning $1,000 is not a
certain outcome (state of nature), the person finds that the probability of winning is
0.001. Based on this information, the following payoff table can be constructed:
Based on the expected monetary value of buying a ticket, what is the best decision?
A. Buy
B. Don’t buy
C. Lose
D. Win
If the variance is 3.6 grams, what is the standard deviation?
A. 0.600
B. 1.897
C. 6.000
D. 12.96
What is a requirement that must be met before the Kruskal-Wallis one-way analysis of
variance by ranks test can be applied?
A. Populations must be normal or near normal.
B. Populations must be independent.
C. Population standard deviations must be equal.
D. Data must be at least interval level.
Consider a company that wishes to verify that an incoming product meets the stipulated
requirements by screening the products using a statistical sampling plan. If the sample
inspection reveals that a lot was accepted, yet it had more defects than it should, this is
referred to as:
A. a Type I error.
B. producer’s risk.
C. consumer’s risk.
D. a sampling error.
The sum of the differences between sample observations and the sample mean is equal
to _______.
A. Zero
B. The mean deviation
C. The range
D. The standard deviation
A machine shop has 100 drill presses and other machines in constant use. The
probability that a machine will become inoperative during a given day is 0.002. During
some days, no machines are inoperative, but on other days, one, two, three, or more are
broken down. What is the probability that fewer than two machines will be inoperative
during a particular day?
A. 0.0200
B. 0.1637
C. 0.8187
D. 0.9824
Data for fuel oil and gasoline purchased at wholesale prices for 2006 and 2010 are
shown next.
What is Paasche’s price index?
A. 116.45
B. 116.71
C. 116.67
D. 131.56
Consider a multiple regression analysis involving 14 independent variables and 150
observations, with SSE = 180 and SS Total = 600. The coefficient of multiple
determination is ______.
A. 0.70
B. 0.40
C. 0.21
D. 0.30
The mean of all the sample means is _______.
A.
B.
C. σ
D. α
An investigation of the effectiveness of a training program to improve customer
relationships included a pre-training and post-training customer survey. To compare the
differences, they computed (post-training survey score – pre-training survey score).
Seven customers were randomly selected and completed both surveys. The results
follow.
This analysis is an example of _____________.
A. A one-sample test of means
B. A two-sample test of means
C. A paired t-test
D. A test of proportions
The following linear trend equation was developed for annual sales from 2005 to 2009,
with 2005 as the base year. Ŷ = 500 + 60t (in $thousands). What are the estimated
sales for 2010 (in $thousands)?
A. $500
B. $860
C. $1,040
D. $1,100
Auditors may select every 20th file starting with the 5th file in the top drawer. Then, file
numbers 25, 45, 65, 85, . . . are selected. This type of sampling is called ___________.
A company set up a kiosk in the Mall of America for several hours and asked randomly
selected people which color cell phone was their favorite. The results follow:
What is an outcome of this experiment?
The following data was collected comparing gasoline prices and quantities (millions of
gallons).
Compute the Paasche price index to compare gas prices in 2010 to 2000.
Six people have declared their intentions to run for a seat on the school board in the
next local election. A poll is conducted during the campaign among 1,020 randomly
sampled voters to determine if there is any clear preference among the voters. The
responses are shown next.
At the 1% level of significance, what is your decision regarding the null hypothesis?
Describe the uniform distribution.
For the standard normal distribution, the z score that corresponds with the 85th
percentile is ________.
As the degrees of freedom increase, the shape of a chi-square distribution approaches a
______________ distribution.
To compare the effect of weather on sales of soft drinks, a distributor surveyed people
in two regions of the country and asked if they purchased soft drinks in the last month.
The following are the results. The distributor would like to know if there is a difference
in sales between the two regions.
What is the null hypothesis?
The z or t value that separates the region of rejection from the region of non-rejection is
called a __________________.
Among 200 people surveyed, 66 people or 0.33% preferred the product. 0.33% is called
the _______________.