The least squares technique minimizes the sum of the squares of the vertical distances
between the actual Y values and the predicted values of Y.
If 95% and 98% confidence intervals were developed to estimate the
To apply the special rule of addition, the events must be mutually exclusive.
The standard normal distribution is a special normal distribution with a mean of 0 and a
standard deviation of 1.
Mean charts are designed to determine whether a process is in or out of control based
on sample means.
If the null hypothesis is TRUE and the researchers reject it, a ________ error has been
made.
Stepwise regression analysis is a method that assists in selecting the most significant
variables for a multiple regression equation.
For any data set, Chebyshev’s theorem estimates the proportion of observations that
occurs within k standard deviations of the mean, where k is greater than 1.0.
The F distribution’s curve is positively skewed.
To convert a frequency distribution to a relative frequency distribution, divide each
class frequency by the number of classes.
To summarize the gender of students attending a college, the number of classes in a
frequency distribution depends on the number of students.
One purpose of quality control is to reduce the costs associated with producing and
delivering poor quality goods and services.
Pareto charts are based on the 80-20 rule, which says 80% of the factors cause 20% of
the problem.
A group of normal distributions can have equal arithmetic means but different standard
deviations.
The central limit theorem states that for a sufficiently large sample the sampling
distribution of the means of all possible samples of size n generated from the population
will be approximately normally distributed with the mean of the sampling distribution
equal to σ2 and the variance equal to σ2/n.
A stem-and-leaf diagram shows the actual data values.
To construct a binomial probability distribution, the mean must be known.
The level of significance is the probability of rejecting the null hypothesis when it is
actually
Extremely high or low scores affect the value of the median.
Based on the central limit theorem, the sample mean can be used as a good estimator of
the population mean, assuming that the size of the sample is sufficiently large.
A university surveyed recent graduates of the English Department for their starting
salaries. Four hundred graduates returned the survey. The average salary was $25,000.
The population standard deviation was $2,500. What is the 95% confidence interval for
the mean salary of all graduates from the English Department?
A. [$22,500, $27,500]
B. [$24,755, $25,245]
C. [$24,988, $25,012]
D. [$24,600, $25,600]
The national sales manager for “I colored this” (ICT) T-shirts provides all salespersons
with the payoff table shown next, giving the estimated profit when a retailer purchases
from one to four dozen T-shirts. The probability of demand for each state of nature is
also shown.
What is the maximum payoff under conditions of certainty?
A. 120
B. 240
C. 360
D. 480
A bottling company offers three kinds of delivery service: instant, same day, and within
five days. The profit per delivery varies according to the kind of delivery. The profit for
an instant delivery is less than the other kinds because the driver has to go directly to a
grocery store with a small load and return to the bottling plant. To find out what effect
each type of delivery has on the profit picture, the company summarized the data in the
following table based on deliveries for the previous quarter.
What is the weighted mean profit per delivery?
A. $72
B. $110
C. $142
D. $97
A one-tailed sign test is used to test for differences between two populations at the 0.10
level of significance. There were nine pluses and five minuses. What is the decision
regarding the null hypothesis?
A. Fail to reject the null hypothesis.
B. Reject the null hypothesis.
C. Neither reject nor fail to reject the null hypothesis.
D. Should have used a paired t test.
Below is the information for a completely randomized experimental design involving
four treatments, where 12 observations were recorded for each treatment for a total of
48 observations.
SST = 210 (Sum of Squares Between Groups)
SS Total = 840 (Sum of Squares Total)
The computed value of F, or the test statistic, is ______.
A. 0.25
B. 12.0
C. 4.88
D. 8.0
Which approach to probability assumes that the events are equally likely?
A. Classical
B. Empirical
C. Subjective
D. Mutually exclusive
In multiple regression analysis, residuals (Y – Ŷ) are used to __________.
A. Provide a global test of a multiple regression model
B. Evaluate the assumption of linearity
C. Calculate the variance inflation factor
D. Compare two regression coefficients
The weight of trucks traveling on a particular section of I-475 has a population mean of
15.8 tons and a population standard deviation of 4.2 tons. What is the probability a state
highway inspector could select a sample of 49 trucks and find the sample mean to be
14.3 tons or less?
A. 0.0062
B. 0.3632
C. 0.1368
D. 0.4938
The cause-and-effect chart is an example of a:
A. range chart.
B. Pareto chart.
C. control chart.
D. fishbone diagram.
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 analysis shows the following results:
What is the regression equation?
A. = 2.195 – 12.201X
B. = -12.201 + 2.195X
C. = 12.201 + 2.195X
D. = 2.195 + 12.201X
The net weights (in grams) of a sample of bottles filled by a machine manufactured by
Edne, and the net weights of a sample filled by a similar machine manufactured by
Orno, Inc., are:
Testing the claim at the 0.05 level that the mean weight of the bottles filled by the Orno
machine is greater than the mean weight of the bottles filled by the Edne machine, what
is the critical value? Assume equal standard deviations for both samples.
A. +2.179
B. +2.145
C. +1.782
D. +1.761
A study of interior designers’ opinions with respect to the most desirable primary color
for executive offices showed the following:
What is the probability that a designer does not prefer red?
A. 1.00
B. 0.77
C. 0.73
D. 0.23
Refer to the following distribution of commissions:
To plot a cumulative frequency distribution, the first coordinate would be _________.
A. X = 0, Y = 600
B. X = 500, Y = 3
C. X = 3, Y = 600
D. X = 600, Y = 0
Consider a three-year moving average. The weights given to each period are:
A. different, with the oldest year receiving the most weight.
B. the same.
C. different, with the first year receiving the most weight.
D. different, with the median year receiving the most weight.
To evaluate the assumption of linearity, a multiple regression analysis should include
___________.
A. A calculation of variance inflation factors
B. Hypothesis tests of individual regression coefficients
C. Scatter diagrams of the dependent variable plotted as a function of each independent
variable
D. An ANOVA table
Using the following information:
What is the coefficient of determination? Round the percentage to one decimal point.
A. 91.8%
B. 8.2%
C. 90.0%
D. 136.9%
The weekly mean income of a group of executives is $1,000 and the standard deviation
of this group is $100. The distribution is normal. What percent of the executives have
an income of $925 or less?
A. About 15%
B. About 85%
C. About 50%
D. About 23%
A distributor of personal computers has five locations in a city. In the year’s first
quarter, the sales in units were:
For a goodness-of-fit test that sales were the same for all locations, what is the critical
value at the 0.01 level of risk?
A. 7.779
B. 15.033
C. 13.277
D. 5.412
Why are unequal class intervals sometimes used in a frequency distribution?
A. To avoid a large number of empty classes
B. For the sake of variety in presenting the data
C. To make the class frequencies smaller
D. To avoid the need for midpoints
Given the following trend equation based on five years of annual sales (in millions of
dollars), beginning in 2005:
Ŷ = 4.53 + 1.54t
The estimated value for 2008 is ______.
A. 9.15
B. 10.69
C. 12.23
D. 6.07
A time series is a collection of data that _______________.
A. records past performance
B. records future performance
C. is limited to yearly data
D. is limited to quarterly data
For the following distribution:
What is the mean of the distribution?
A. 2.1
B. 1.13
C. 0.113
D. 1.5
In multiple regression analysis, residuals (Y – Ŷ) should be ____________.
A. Qualitative variables
B. Significantly different from zero
C. Correlated
D. Normally distributed with a mean of zero
The Office of Student Services at a large western state university maintains information
on the study habits of its full-time students. Their studies indicate that the mean amount
of time undergraduate students study per week is 20 hours. The hours studied follows
the normal distribution with a standard deviation of six hours. Suppose we select a
random sample of 144 current students. What is the probability that the mean of this
sample is less than 19.25 hours?
A. 0.4332
B. 0.8664
C. 0.0668
D. 0.0181
A soap manufacturer is experimenting with several formulas of soap powder. Three of
the formulas were selected for further testing by a panel of homemakers. The ratings for
the three formulas are as follows:
What is the number of degrees of freedom?
The measure of central location with the smallest value in a positively skewed
distribution is the _________.
A survey of property owners’ opinions about a street-widening project was taken to
determine if owners’ opinions were related to the distance between their home and the
street. A randomly selected sample of 100 property owners was contacted and the
results are shown next.
What is your decision regarding the null hypothesis at the 5% level of significance?
For the following data, what is the interquartile range?
A committee that is studying employer-employee relations proposed that each employee
would rate his or her immediate supervisor, and in turn the supervisor would rate each
employee. To find reactions regarding the proposal, 120 office personnel and 160 plant
personnel were selected at random. Seventy-eight of the office personnel and 90 of the
plant personnel were in favor of the proposal. We test the hypothesis that the population
proportions are equal with a 0.05 significance level. What is our decision?
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 company should you choose if the economy is unfavorable?