Which of the following is NOT necessary to determine how large a sample to select
from a population?
A. The level of confidence in estimating the population parameter
B. The size of the population
C. The maximum allowable error in estimating the population parameter
D. An estimate of the population variation
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 hypothesis tests for the individual regression coefficients, ____________.
A. All the regression coefficients are not equal to zero
B. “Job” is the only significant variable in the model
C. Only months of service and gender are significantly related to monthly salary
D. “Service” is the only significant variable in the model
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:
At the 1% level of significance, what is the decision?
A. Reject the null hypothesis and conclude the variances are different.
B. Fail to reject the null hypothesis and conclude the variances are different.
C. Reject the null hypothesis and conclude the variances are the same.
D. Fail to reject the null hypothesis and conclude the variances are the same.
A lamp manufacturer designed five lamp bases and four lampshades that could be used
together. How many different arrangements of base and shade can be offered?
A. 5
B. 10
C. 15
D. 20
Which of the following is true regarding the normal distribution?
A. The mean, median, and mode are all equal.
B. It has two modes.
C. It is asymmetrical.
D. The points of the curve meet the x-axis at z = -3 and z = 3.
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
For a hypothesis test comparing two population means, the combined degrees of
freedom are 24. Which of the following statements about the two sample sizes is NOT
true? Assume the population standard deviations are equal.
A. n1 = 11; n2 = 13
B. n1 = 12; n2 = 14
C. n1 = 13; n2 = 13
D. n1 = 10; n2 = 16
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%
Suppose that an automobile manufacturer designed a radically new lightweight engine
and wants to recommend the grade of gasoline that will have the best fuel economy.
The four grades are regular, economy, premium, and super premium. The test car made
three trial runs on the test track using each of the four grades. The miles per gallon were
recorded for each grade. At the 0.05 level, what is the critical value of F used to test the
hypothesis that the miles per gallon for each fuel are the same?
A. 1.96
B. 4.07
C. 2.33
D. 12.00
When testing for differences between treatment means, the degrees of freedom for the t
statistic are ___________.
A. k
B. (n – 1)
C. (n – k)
D. (1/n1 + 1/n2)
What is the following table called?
A. Histogram
B. Frequency polygon
C. Cumulative frequency distribution
D. Frequency distribution
A sample of experienced typists revealed that their mean typing speed is 87 words per
minute and the median typing speed is 73 words per minute. The standard deviation of
typing speed is 16.9 words per minute. What is the Pearson coefficient of skewness?
A. -2.5
B. -4.2
C. +4.2
D. +2.5
The size of the sampling error is ________.
A. Directly related to the sample sizein other words, the larger the sample size, the
larger the sampling error
B. Directly related to the population meanin other words, the larger the mean, the larger
the sampling error
C. Inversely related to the sample sizein other words, the larger the sample size, the
smaller the sampling error
D. Inversely related to the population standard deviationin other words, the smaller the
standard deviation, the larger the sampling error
Refer to the following frequency distribution on days absent during a calendar year by
employees of a manufacturing company:
How many employees were absent six days or more?
A. 8
B. 4
C. 22
D. 31
Sponsors of a local charity decided to attract wealthy patrons to its $500-a-plate dinner
by allowing each patron to buy a set of 20 tickets for the gaming tables. The chance of
winning a prize for each of the 20 plays is 50-50. If you bought 20 tickets, what is the
chance of winning 15 or more prizes?
A. 0.250
B. 0.021
C. 0.006
D. 0.750
If all the plots on a scatter diagram lie on a straight line, what is the standard error of
estimate?
A. -1
B. +1
C. 0
D. Infinity
Your height and weight are examples of which level of measurement?
A. Nominal
B. Ordinal
C. Interval
D. Ratio
The regression equation is Ŷ = 29.29 – 0.96X, the sample size is 8, and the standard
error of the slope is 0.22. What is the test-statistic to test the significance of the slope?
A. z = -4.364
B. z = +4.364
C. t = -4.364
D. t = -0.960
David’s gasoline station offers 4 cents off per gallon if the customer pays in cash and
does not use a credit card. Past evidence indicates that 40% of all customers pay in
cash. During a one-hour period, 15 customers buy gasoline at this station. What is the
probability that all 15 pay in cash?
A. 0.0
B. 0.1
C. 0.9
D. 1.0
Sampling error is defined as _________.
A.
B. σ
C. σ/n
D. N – n
The best example of a null hypothesis for testing an individual regression coefficient is
__________.
A. H0: β1 = β2 = β3 = β4 = 0
B. H0: 1 = 2 = 3 = 4 = 0
C. H0: β1 = 0
D. H0: β1 ≠ 0
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.
What is the predicted GPA for a student with an IQ of 108, 32 hours spent studying per
week, and a high school average of 82?
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 between 19 hours and 20 hours?
A. 2.00
B. 0.4772
C. -2.00
D. Cannot be calculated based on the given information.
A disadvantage of using an arithmetic mean to summarize a set of data is that
__________.
A. The arithmetic mean sometimes has two values
B. It can be used for interval and ratio data
C. It is always different from the median
D. It can be biased by one or two extremely small or large values
Refer to the following breakdown of responses to a survey of “Are you concerned about
being tracked while connected to the Internet?”
What type of chart should be used to describe the frequency table?
A. A pie chart
B. A bar chart
C. A histogram
D. A frequency polygon
In hypothesis testing, what is the level of significance?
A. The risk of rejecting the null hypothesis when it is true.
B. A value symbolized by the Greek letter α.
C. A value between 0 and 1.
D. It is selected before a decision rule can be formulated.
E. All apply.
A developer of a new subdivision wants to build homes that are all different. There are
three different interior plans that can be combined with any of five different home
exteriors. How many different homes can be built?
A. 8
B. 10
C. 15
D. 30
A group of statistics students decided to conduct a survey at their university to estimate
the average (mean) amount of time students spent studying per week. They sampled
554 students and found a mean of 22.3 hours per week. Assuming a population standard
deviation of six hours, what is the 95% level of confidence?
A. [21.80, 22.80]
B. [16.3, 28.3]
C. [21.64, 22.96]
D. [20.22, 22.0]
A hypothesis regarding the weight of newborn infants at a community hospital is that
the mean is 6.6 pounds. A sample of seven infants is randomly selected and their
weights at birth are recorded as 9.0, 7.3, 6.0, 8.8, 6.8, 8.4, and 6.6 pounds. The null
hypothesis is ______.
A. H0: = 6.6
B. H0: ≥ 6.6
C. H0: > 7.6
D. H0: ≤ 7.6
Unorganized data is referred to as ________ data.
In multiple regression analysis, when the independent variables are highly correlated,
this situation is called __________________.
A. Autocorrelation
B. Multicollinearity
C. Homoscedasticity
D. Curvilinearity
If the correlation between sales and advertising is +0.6, _____% of the variation in sales
can be attributed to advertising.
The American Auto Association reports the mean price per gallon of regular gasoline is
$3.10, with a population standard deviation of $0.20. Assume a random sample of 16
gasoline stations is selected and their mean cost for regular gasoline is computed. What
is the probability that the difference between the sample mean and the population mean
is less than 0.01?
The Sea Mist Hotel collects customer satisfaction data daily. Yesterday, the hotel was
99% occupied and the manager wanted to quickly assess customer satisfaction. She
randomly selected 10 scores. 100 points is the maximum score. The mean score is 82.1.
The 10 scores were:
What is the variance?
There are 10 flights from Minneapolis to St. Cloud each day. The probability that any
one flight is late is 0.05. Using the binomial probability formula, what is the probability
that 1 or more are late?
In a bar chart, why are there spaces between the bars on the horizontal axis?
The measure of central location that uses all of the observations in its calculation is
called the ___________.
Increasing sample sizes result in _______________ interval estimates of a population
parameter.
If every kth item in the population sequence is selected, you should use the
__________________ sampling method.
For any probability distribution, the mean is calculated as a weighted mean. The
weights are the ______________.
A chi-square goodness-of-fit test is used to determine how well an observed distribution
fits an _________ distribution.
A scale used to measure a quantitative variable is either _______________ or
______________.
The mean of a Poisson distribution is calculated using ____.
Why are goodness-of-fit hypothesis tests comparing observed data to a normal
distribution important in the field of statistics?
The minimum and maximum values of the coefficient of determination are ________.
In an ANOVA for a multiple regression analysis, the three sources of variation are
__________________.
The waiting time for patients at a local walk-in health clinic follows a normal
distribution with a mean of 15 minutes and a population standard deviation of 5
minutes. The quality-assurance department sampled 50 patients and found that the mean
waiting time was 13.25 minutes. At the 0.025 significance level, decide if the sample
data support the claim that the mean waiting time is less than 15 minutes. State your
decision in terms of the null hypothesis.
Ages (rounded to the nearest whole year) of employees at a large company were
grouped into a distribution with the following class limits:
20 up to 30
30 up to 40
40 up to 50
50 up to 60
60 up to 70
The class limits for the class 50 up to 60 are _______ and ______.
About ______% of the area under the normal curve is within plus two and minus two
standard deviations of the mean.