The binomial probability distribution is always negatively skewed.
An example of a dummy variable is “time to product’s first repair” in years.
A pie chart is similar to a relative frequency distribution.
The ordinal level of measurement is considered the “lowest” level of measurement.
Statistical decision theory is defined as the collection of techniques a decision maker
can apply to choose the best alternative action.
In a two-way ANOVA with interaction, there are two factor effects and an interaction
effect.
The coefficient of determination is the proportion of total variation in Y that is
explained by X.
The normal distribution can be used to approximate a binomial distribution when nπ is
less than 5.
Which is TRUE for a binomial distribution?
A. There are ten or more possible outcomes.
B. The probability of success remains the same from trial to trial.
C. The value of π is equal to 1.50.
D. It approximates the Poisson distribution.
Optimists advocate a maximax strategy.
In a multiple regression analysis, if the regression coefficient of a dummy variable is
significant and has a sample value of 100, then the dummy variable’s effect on the
dependent variable is an increase of 100.
The central limit theorem states that if the sample size, n, is sufficiently large, the
sampling distribution of the means will be approximately normal, even when the
population is skewed or uniform.
A “continuity correction factor” is used to compute probabilities when using the normal
distribution to approximate the binomial distribution.
A manufacturer of headache medicine claims it is 70% effective within a few minutes.
That is, out of every 100 users, 70 get relief within a few minutes. A group of 12
patients are given the medicine. If the claim is TRUE, what is the probability that eight
have relief within a few minutes?
A. 0.001
B. 0.168
C. 0.667
D. 0.231
The random variable for a Poisson probability distribution can assume an infinite
number of values.
If two events A and B are mutually exclusive, what does the special rule of addition
state?
A. P(A or B) = P(A) + P(B)
B. P(A and B) = P(A) + P(B)
C. P(A and/or B) = P(A) + P(B)
D. P(A or B) = P(A) – P(B)
The following table shows the sales for a resort hotel recorded over the past year. The
seasonal indexes for each quarter are also provided. To track the trend for these four
quarters, use the indexes to deseasonalize the sales data.
Overall, sales are __________.
A quality control chart is used to monitor the customer wait time at a local call center.
Sample means of five times are averaged and plotted over time. Over the last hundred
sample means, one sample mean was outside a control limit. The chart shows:
A. chance variation.
B. standard variation.
C. assignable variation.
D. total variation.
The manager of Paul’s fruit and vegetable store is considering the purchase of a new
seedless watermelon from a wholesale distributor. Since this seedless watermelon costs
$4, will sell for $7, and is highly perishable, he only expects to sell between six and
nine of them. What is the payoff value for the purchase of seven watermelons when the
demand is for six watermelons?
A. 14
B. 18
C. 21
D. 24
The following is a binomial probability distribution with n = 3 and π = 0.20.
The variance of the distribution is _________.
A. 1.5
B. 3.0
C. 0.69
D. 0.48
What is the general form of the regression equation?
A. Ŷ = ab
B. Ŷ = a + (bX)
C. Ŷ = (a + b)X
D. Ŷ = abX
Mileage tests were conducted on a randomly selected sample of 100 newly developed
automobile tires. The mean tread wear was 50,000 miles, with a standard deviation of
3,500 miles. What is the best estimate of the average tread life in miles for the entire
population of these tires?
A. 50,000
B. 3,500
C. 500
D. 35
A nonparametric test cannot be applied when the data are:
A. nominal.
B. ordinal.
C. interval.
D. ratio.
In a scatter diagram, we describe the relationship between __________.
A. Two variables measured at the ordinal level
B. Two variables, one measured as an ordinal variable and the other as a ratio variable
C. Two variables measured at the interval or ratio level
D. A variable measure on the interval or ratio level and time
Analysis of variance is used to _____________.
A. Compare nominal data
B. Compute a t test
C. Compare population proportions
D. Simultaneously compare several population means
The following data was collected from a simple random sample of a population of
college freshmen. It represents their ages on the first day of the fall semester.
17 21 19 18 18 19
The point estimates of the population mean and standard deviation are:
A. 18 and 1.75.
B. 19 and 1.78.
C. 17.67 and 1.63.
D. 18.67 and 1.36.
Some important uses of the chi-square distribution include:
A. testing for goodness-of-fit.
B. determining whether a variable appears to follow some specified distribution.
C. testing for the association of two categorical variables.
D. All of these are TRUE.
What is the area under the normal curve between z = -1.0 and z = -2.0?
A. 0.0228
B. 0.3413
C. 0.1359
D. 0.4772
To use the sign test with paired data, trials must:
A. be independent.
B. be dependent.
C. have three or more outcomes.
D. have a probability of 0.50.
It is claimed that in a bushel of peaches, less than 10% are defective. A sample of 400
peaches is examined and 50 are found to be defective. What is the sample proportion?
A. 0.10
B. 0.125
C. 40
D. 0.40
Ball-Bearings, Inc. produces ball bearings automatically on a Kronar BBX machine.
For one of the ball bearings, the mean diameter is set at 20.00 mm (millimeters). The
standard deviation of the production over a long period of time was computed to be
0.150 mm. What percent of the ball bearings will have diameters of 20.27 mm or more?
A. 41.00%
B. 12.62%
C. 3.59%
D. 85.00%
The college of business was interested in comparing the attendance for three different
class times for a business statistics class. The data follow.
What is the blocking variable?
A. Day
B. Class time
C. Tuesday
D. 8:00 a.m. class
A question in a market survey asks for a respondent’s favorite car color. Which measure
of central location should be used to summarize this question?
A. Mode
B. Median
C. Mean
D. Standard deviation
Data for selected vegetables purchased at wholesale prices for 1995 and 2007 are
shown next.
What is the simple price relative for carrots?
In relative terms, a _______ standard deviation leads to a narrower confidence interval.
A new printing machine is set or calibrated to print 25 copies per minute. On each of
four days, the printer’s output is measured five times. The data will be used to construct
a process control chart to monitor the printing process. The results of the printing
process are in the following table.
What is the value of the upper control limit factor for a range chart?
In multiple regression analysis, a dummy variable is coded as a _______.
The purpose of an index is to _____________________________________.
How are residual plots drawn and used to evaluate the assumptions of linear multiple
regression?