A student was interested in the cigarette smoking habits of college students and
collected data from an unbiased random sample of students. The data is summarized in
the following table:
Why is the table NOT a frequency distribution?
A. The number of males does not equal the sum of males that smoke and do not smoke.
B. The classes are not mutually exclusive.
C. There are too many classes.
D. Class limits cannot be computed.
A recent study focused on the amount of money single men and women save monthly.
The information is summarized next. Assume that the population standard deviations
are equal.
At the .01 significance level, do women save more money than men? What is the
critical value for this hypothesis test?
A. +6.213
B. +2.369
C. +2.632
D. +2.40
An electronics firm sells four models of stereo receivers, three amplifiers, and six
speaker brands. When the four types of components are sold together, they form a
‘system.” How many different systems can the electronics firm offer?
A. 36
B. 18
C. 72
D. 144
Refer to the following wage breakdown for a garment factory.
What is the class midpoint for the class with the greatest frequency?
A. $5.50
B. $8.50
C. $11.50
D. $14.50
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
For the following distribution:
What is the mean of the distribution?
A. 2.1
B. 1.5
C. 0.441
D. 2
A group of employees of Unique Services will be surveyed about a new pension plan.
In-depth interviews with each employee selected in the sample will be conducted. The
employees are classified as follows.
What is the probability that the first person selected is a supervisor and in management?
A. 0.00
B. 0.06
C. 0.15
D. 0.21
A consumer products company wants to increase the absorption capacity of a sponge.
Based on past data, the average sponge could absorb 3.5 ounces. After the redesign, the
absorption amounts of a sample of sponges were (in ounces): 4.1, 3.7, 3.3, 3.5, 3.8, 3.9,
3.6, 3.8, 4.0, and 3.9. At the 0.01 level of significance, what is the decision rule to test if
the new design increased the absorption of the sponge?
A. Reject null hypothesis if computed t is less than 2.580.
B. Reject null hypothesis if computed t is greater than 2.821.
C. Reject null hypothesis if computed z is 1.96 or larger.
D. Reject null hypothesis if computed t is less than 2.764.
A local retail company wants to estimate the mean amount spent by customers. Their
store’s budget limits the number of surveys to 225. What is their maximum error of the
estimated mean amount spent for a 99% level of confidence and an estimated standard
deviation of $10.00?
A. $10
B. $1.00
C. 1%
D. $1.72
A large department store examined a sample of the 18 credit card sales and recorded the
amounts charged for each of three types of credit cards: MasterCard, Visa, and
Discover. Six MasterCard sales, seven Visa, and five Discover sales were recorded. The
store used an ANOVA to test if the mean sales for each credit card were equal. What are
the degrees of freedom for the F statistic?
A. 18 in the numerator, 3 in the denominator
B. 3 in the numerator, 18 in the denominator
C. 2 in the numerator, 15 in the denominator
D. 6 in the numerator, 15 in the denominator
What type of variable is the number of gallons of gasoline pumped by a filling station
during a day?
A. Qualitative
B. Continuous
C. Attribute
D. Discrete
The average cost of tuition and room and board at a small private liberal arts college is
reported to be $8,500 per term, but a financial administrator believes that the average
cost is higher. A study conducted using 350 small liberal arts colleges showed that the
average cost per term is $8,745. The population standard deviation is $1,200. Let α =
0.05. What are the null and alternative hypotheses for this study?
A. H0: ≤ $9,000; H1: > $9,000
B. H0: ≥ $9,000; H1: < $9,000
C. H0: ≤ $8,500; H1: > $8,500
D. H0: ≥ $8,500; H1: < $8,500
Which statement(s) is/are correct about the t distribution?
A. The mean is zero.
B. Its shape is symmetric.
C. Its dispersion is based on degrees of freedom.
D. All apply.
A cola-dispensing machine is set to dispense a mean of 2.02 liters into a container
labeled 2 liters. Actual quantities dispensed vary and the amounts are normally
distributed with a standard deviation of 0.015 liters. What is the probability a container
will have less than 2 liters?
A. 0.0918
B. 0.3413
C. 0.1926
D. 0.8741
What is the interpretation of a 96% confidence level?
A. There’s a 96% chance that the given interval includes the true value of the population
parameter.
B. Approximately 96 out of 100 such intervals would include the true value of the
population parameter.
C. There’s a 4% chance that the given interval does not include the true value of the
population parameter.
D. The interval contains 96% of all sample means.
An experiment may have ____________.
A. Only one outcome
B. Only two outcomes
C. One or more outcomes
D. Several events
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
What type of variable is the number of robberies reported in your city?
A. Attribute
B. Continuous
C. Quantitative
D. Qualitative
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
What type of variable is the number of auto accidents reported in a given month?
A. Interval
B. Ratio
C. Continuous
D. Discrete
The joint probability of two events that are not independent, P(A and B), is computed as
_______________.
Refer to the following breakdown of responses to a survey of “How confident are you
that you saved enough to retire?”
What type of chart should be used to show relative class frequencies?
A. A pie chart
B. A bar chart
C. A histogram
D. A frequency polygon
It has been hypothesized that overall academic success for college freshmen as
measured by grade point average (GPA) is a function of IQ scores, X1, hours spent
studying each week, X2, and one’s high school average, X3. Suppose the regression
equation is . The multiple standard error is
6.313 and R2 = 0.826.
Which independent variable has the smallest effect on GPA?
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
A survey includes a question regarding marital status that has the following responses:
single, married, divorced, separated, or widowed. What is the scale of measurement for
this question?
A. Ratio
B. Interval
C. Ordinal
D. Nominal
Recently, students in a marketing research class were interested in the driving behavior
of students. Specifically, the marketing students were interested in finding out if
exceeding the speed limit was related to gender. They collected the following responses
from 100 randomly selected students:
The null hypothesis for the analysis is ____________.
A. There is no relationship between gender and speeding
B. The correlation between driving behavior and gender is zero
C. As driving behavior increases, gender increases
D. The mean of driving behavior equals the mean of gender
A true/false test consists of six questions. If you guess the answer to each question,
what is the probability of getting all six questions correct?
A. 0
B. 0.016
C. 0.062
D. 0.250
For any chi-square goodness-of-fit test, the number of degrees of freedom is found by
______.
A. n – k – 1
B. k – 1
C. n + 1
D. n + k
The time to fly between New York City and Chicago is uniformly distributed with a
minimum of 120 minutes and a maximum of 150 minutes. What is the probability that a
flight is between 125 and 140 minutes?
A. 1.00
B. 0.50
C. 0.33
D. 10.00
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. What are the standard normal z-statistics for the
class limits?
A. -20 and 20
B. -2.5 and -2.0
C. 2.0 and 2.5
D. -50 and -40
The employees of Cartwright Manufacturing are awarded efficiency ratings. The
distribution of the ratings approximates a normal distribution. The mean is 400, the
standard deviation 50. What is the area under the normal curve between 400 and 482?
A. 0.5000
B. 0.4495
C. 0.3413
D. 0.4750
Based on the Nielsen ratings, the local CBS affiliate claims its 11 p.m. newscast reaches
41% of the viewing audience in the area. In a survey of 100 viewers, 36% indicated that
they watch the late evening news on this local CBS station. What is the alternate
hypothesis?
A. H1: π = 0.36
B. H1: π = 0.41
C. H1: π ≠ 0.41
D. H1: ≠ 0.41
The critical t statistic for the alternative hypothesis, H1: < 12, a 0.005 level of
significance, and a sample size of 20 is ______.
We are interested in knowing if the following frequency distribution is normally
distributed. The population mean and standard deviation of the data are 600 and 160,
respectively.
What are the standard normal z-statistic class limits for the “400 up to 600” class?
The arrival of customers at a service desk follows a Poisson distribution. If they arrive
at a rate of two every five minutes, what is the probability that no customers arrive in a
five-minute period?
A sample mean is a _______________ estimate of the population mean.
We are interested in knowing if the following frequency distribution is normally
distributed. The population mean and standard deviation of the data are 600 and 160,
respectively.
If the distribution was normally distributed, what is the probability that an observation
would be a member of the “400 up to 600” class?
A company’s human resources department was interested in the average number of
years that a person works before retiring. The sample of size 11 follows:
Based on the values of the arithmetic mean, median, and mode, what is the most likely
shape of the distribution?
A university has 1,000 computers available for students to use. Each computer has a
250-gigabyte hard drive. The university wants to estimate the space occupied on the
hard drives. A random sample of 100 computers showed a mean of 115 gigabytes used
with a standard deviation of 20 gigabytes. What is the standard error of the mean?
A manufacturer claims that less than 1% of all its products do not meet the minimum
government standards. A survey of 500 products revealed that 10 did not meet the
standard. Thus, the computed z statistic is ______________.
A sample of five full-service gasoline stations, each carrying three grades of gasoline,
was taken, and the price per liter (to the nearest cent) was recorded for each grade of
gasoline, as shown in the following table.
What is the modal price of unleaded gas?
When dependent samples are used to test for differences in the means, we compute
________________ differences.
Five students were given a page of problems with instructions to solve as many as they
could in one hour. The five students solved the following number of problems: 12, 10,
8, 6, and 4. What is the arithmetic mean number of minutes required per problem?
To apply the special rule of addition, the events must be _________.
The following is an example of a ___________________________.