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 treatment variable?
A. Day
B. Class time
C. Tuesday
D. 8:00 a.m. class
The following table shows sample salary information for employees with bachelor’s and
associate degrees for a large company in the Southeast United States.
The point estimate of the difference between the means of the two populations is
______.
A. 32
B. 9
C. -4.5
D. 4.5
In the Kruskal-Wallis test for the following data, what are the degrees of freedom?
A. 8
B. 2
C. 6
D. 3
A bank asks customers to evaluate the drive-thru service as good, average, or poor.
Which level of measurement is this classification?
A. Nominal
B. Ordinal
C. Interval
D. Ratio
The Equal Employment Opportunity Act requires employers to classify their employees
by gender and national origin. Which level of measurement is this?
A. Nominal
B. Ordinal
C. Interval
D. Ratio
What is a disadvantage of the range as a measure of dispersion?
A. It is based on only two observations.
B. It can be distorted by a large mean.
C. It is not in the same units as the original data.
D. It has no disadvantage.
A random sample of 30 executives from companies with assets over $1 million was
selected and asked for their annual income and level of education. The ANOVA
comparing the average income among three levels of education rejected the null
hypothesis. The mean square error (MSE) was 243.7. The following table summarized
the results:
When comparing the mean annual incomes for executives with undergraduate and
master’s degrees or more, which of the following 95% confidence interval can be
constructed?
A. 2.0 2.052 * 6.52
B. 2.0 3.182 * 6.52
C. 2.0 2.052 * 42.46
D. 2.0 3.182 * 42.46
Two accounting professors decided to compare the variance of their grading procedures.
To accomplish this, they each graded the same 10 exams, with the following results:
What are the degrees of freedom for the denominator of the F ratio?
A. 20
B. 18
C. 10
D. 9
In the Kruskal-Wallis test for the following data, what is the sum of the ranks for
Sample 1?
A. 9
B. 163
C. 3
D. 23
If we reject the null hypothesis, what can we conclude subject to the probability, α?
A. Reject the null with a probability, α, of making a Type I error.
B. The alternative hypothesis is FALSE.
C. The null hypothesis is TRUE.
D. Both the null hypothesis and the alternative hypothesis are TRUE.
For the following distribution:
What is the variance of the distribution?
A. 2.1
B. 0.63
C. 3.9
D. 2.754
A multiple regression model includes the term (X1)(X2). The term implies that:
A. the independent variables are correlated.
B. there is only one independent variable in the regression model.
C. the effect of X1 on the dependent variable is independent of the value of X2.
D. the effect of X1 on the dependent variable depends on the value of X2.
According to the central limit theorem, ____________.
A. the population mean and the mean of all sample means are equal
B. increasing sample size decreases the dispersion of the sampling distribution
C. the sampling distribution of the sample means is approximately normally distributed
D. the sampling distribution of the sample means will be skewed
A supplier delivers an order for 20 electric toothbrushes to a store. By accident, three of
the electric toothbrushes are defective. What is the probability that the first two electric
toothbrushes sold will be returned because they are defective?
A. 3/20 or 0.15
B. 3/17 or 0.176
C. or 0.25
D. 3/190 or 0.01579
A manager at a local bank analyzed the relationship between monthly salary and three
independent variables: length of service (measured in months), gender (0 = female, 1 =
male), and job type (0 = clerical, 1 = technical). The following ANOVA summarizes the
regression results:
Based on the ANOVA and a 0.05 significance level, the global null hypothesis test of
the multiple regression model ___________.
A. Will be rejected and conclude that monthly salary is related to all of the independent
variables
B. Will be rejected and conclude that monthly salary is related to at least one of the
independent variables
C. Will not be rejected
D. Will show a high multiple coefficient of determination
The chi-square distribution becomes more symmetrical as the ____________.
A. Number of variables increases
B. The chi-square value increases
C. Degrees of freedom decrease
D. Degrees of freedom increase
Suppose a package delivery company purchased 14 trucks at the same time. Five trucks
were purchased from manufacturer A, four from manufacturer B, and five from
manufacturer C. The cost of maintaining each truck was recorded. The company used
ANOVA to test if the mean maintenance costs of the trucks from each manufacturer
were equal. To apply the F test, how many degrees of freedom must be in the
denominator?
A. 2
B. 3
C. 11
D. 14
Three different fertilizers were applied to a field of celery. In computing F, how many
degrees of freedom are there in the numerator?
A. 0
B. 1
C. 2
D. 3
If the correlation coefficient between two variables, X and Y, equals zero, what can be
said of the variables X and Y?
A. The variables are not related.
B. The variables are dependent on each other.
C. The variables are highly related.
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. Based on the normal distribution, what is the
probability that an observation would be in this class?
A. 0.4938
B. 0.4772
C. 0.0166
D. -0.0166
The annual income for a sample of 500 part-time students is normally distributed with a
mean income of $30,000 and a standard deviation of $3,000. The income range that
separates the top 25% from the lower 75% is __________.
If we are testing for the difference between two population proportions, it is assumed
that the two samples are large enough that the binomial distribution can be
approximated by ______.
For populations scattered in a wide area, the preferred technique for sampling is
___________.
A student is planning a trip home for the holidays and has three options: car, train, or
jet. The decision depends on if the weather is good or bad. In addition, the student
estimated the costs for each option. The payoff table follows.
What is the value of perfect information?
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 lower control limit (LCL) for the mean chart?
A cell phone salesperson has kept records on the customers who visited his store. Forty
percent of the customers who visited the store were female. Furthermore, the data show
that 35% of the females who visited his store purchased a cell phone, while 20% of the
males who visited his store purchased a cell phone. Let A1 represent the event that a
customer is a female, A2 represent the event that a customer is a male, and B represent
the event that a customer will purchase a phone.
What is the probability that a male customer will purchase a cell phone?
When testing for a difference between the means of two dependent samples, the sample
test statistic is a ______________.
The Kruskal-Wallis test is the nonparametric analogy to a one-way ________.
Elly’s Hotdog Emporium is famous for its chilidogs. Elly’s latest sales indicate that 30%
of the customers order their chilidogs with hot peppers. Suppose 15 customers are
selected at random. What is the probability that between two and six people inclusive
want hot peppers?