Download Cumulative Rev Questions

Review 1 Questions
1. Suppose that random variable X has mean 45 and standard deviation 15, and random variable Y has mean 15
and standard deviation 3. What would be the mean and standard deviation of the random variable X + Y?
A.
B.
C.
D.
E.
Mean 30; standard deviation 9
Mean 30; standard deviation 18
Mean 60; standard deviation 9
Mean 60; standard deviation 15.3
Mean 60; standard deviation 18
2. The following boxplots summarize two data sets labeled A and B
Data Set A
Data Set B
10
20
30
40
50
Which of the following is justified by the boxplots?
I.
II.
III.
Data set A contains more values than data set B.
Data set A has wider range than data set B.
Data set A has a wider interquartile range than data set B.
A. I only
B. II only
C. I and II only
(Skip this question)
D. II and III only
E. I, II, and III
3. A member of congress wants to poll voters in his state regarding various national issues. Which of the
following methods would be an example of “cluster sampling”?
A. Use random numbers to select a random sample of 1000 voters from a voter registration list.
B. Use random numbers to select a random sample of 50 voters from voter registration lists in
of the state’s counties.
each
C. From the voter registration list, select every 50th name on the list
D. Select one random county and poll every registered voter in that county.
E. Place volunteers in 20 locations throughout the state and have each volunteer question
people for one week.
random
4. A student in a geography class wanted to compare the mean size of states in the United States with the mean
size of the provinces of Canada. The student took the average land area of all 50 states of the United Sates and
the average land area of all 10 provinces of Canada computed a t-statistics for a test comparing means from two
independent samples. Which of the following can be valid reasons for stating that the student’s procedure was
an inappropriate approach in this context?
I. Since the distribution of the land areas are not normally distributed, it is invalid to use the tdistribution.
II. Since all the states and provinces are taken in the sample, a hypothesis test is not necessary, since the
population means are known.
III. The land areas of the states and provinces are not independent.
A.
B.
C.
D.
E.
I only
II only
I and II only
I and III only
I, II, and III
5. Which of the following is an advantage of using a stratified sample instead of simple random sample?
A. In a stratified sample, each member of the population is equally likely to be chosen in the sample.
B. In a Stratified sample, certain groups of interest are guaranteed to be represented in the sample.
C. A stratified sample can be done with a smaller sample size.
D. A stratified sample is easier to create than a simple random sample.
E. Significance tests cannot be done with a simple random sample.
6. Suppose that a set of sores on a standardized test is normally distributed, with a mean of 170, and standard
deviation 50. If the professor for the course divides all scores by 2, what would be the new mean and standard
deviation of the set of scores?
A. Mean 170 Standard Deviation 50
B. Mean 170 Standard Deviation 25
C. Mean 85
Standard Deviation 50
D. Mean 85
Standard Deviation 35.35
E. Mean 85 Standard Deviation 25
7. A test has been given in a trigonometry class of 35 students. The mean on the test was 81, with a median of
77, and a standard deviation 16. The teacher indicated that there was one outlier among the scores. If the teacher
removes the outlier from the list of scores, which of the following statements would be true?
A. The mean and median would both go up.
B. The mean and median would both go down.
C. The mean would go up, but the median would stay the same.
D. The median would go up, but the mean would stay the same.
E. The result cannot be determined from the information given
8.Suppose that a newspaper in Wisconsin wants to take a statewide survey concerning issues regarding state
budgetary issues. The newspaper creates a sample by randomly selecting 50 people from each county in the
state. Which of the following terms best describes the type of sample that is being created?
A. A simple random sample
B. A convenience sample
C. A stratified sample
D. A systematic sample
E. A cluster sample
9. Suppose that the night before a national election, the host of a radio show asked callers to call his program
and indicate which of the candidate they would vote for. At the end of the program, the radio show host
indicated that, based on his survey, a certain candidate would likely win, However, on the Election Day, the
candidate lost. Which of the following is most likely the explanation for why the radio show’s survey was
wrong?
A. The survey was voluntary, and only those who wanted to participate did.
B. The question to the callers was slanted, producing incorrect results
C. A large number of callers lied in their responses.
D. The survey was accurate, but many people changed their minds when they voted.
E. The sample size was too small
10. In a study of the effect of volunteerism, the incidence of juvenile delinquency was observed to be higher
among 7th and 8th grade children who were not involved in the volunteer activities. As part of an effort to reduce
juvenile delinquency among 7th and 8th grade children, such children who were involved in a crime were
required to join a volunteer activity. However, the incidence of juvenile delinquency was not reduced among
these children. Which of the following is the most likely explanation for the error in the expectation that the
volunteer activities would reduce the delinquency?
A. The difference between boys and girls involved in delinquency was not considered.
B. There was a correlation between volunteer activities and low delinquency, but the correlation was not strong.
C. There were confounding factors among the children involved in the delinquency.
D. It was assumed that the volunteer activities were the cause of low delinquency, not merely a factor that was
correlated to low delinquency
E. Another sample of children might reveal that juvenile delinquency us actually higher among children who
are involved in volunteer activities
11. A research company desires to test the effect of a drug meant to reduce the effect of migraine headaches.
Two groups are tested. One group is given the drug, and the patients are instructed to indicate whether they feel
relief from the drug. Another group is given a placebo, a fake pill, and also instructed to indicate whether they
feel relief. The test is done as a double-blind study. What is mean by saying the study us “double blind?”
A. neither group knows whether they are receiving the actual drug or the placebo.
B. Neither the patient nor the doctor administering the pill knows whether the pill is the actual drug of the
placebo
C. Not only do the patients not know whether the pill is the actual drug or the placebo, but they also do not
know why they are taking a pill
D. It is not known how many of the patients are taking drugs or the placebo
E. Patients are blindfolded while they are given one of the pills
12. Suppose that a random sample of two values is taken from the population { 1, 3, 4, 8 }. If the sample is
taken without replacement, then the samples have mean µx-bar = 4 and standard deviation σx-bar =1.472. If the
sample is taken with replacement, how would the mean µx-bar and standard deviation σx-bar differ?
A. µx-bar and σx-bar would both stay the same.
B. µx-bar would increase and σx-bar would stay the same.
C. µx-bar would stay the same and σx-bar would increase.
D. µx-bar and σx-bar would both increase.
E. µx-bar would stay the same and σx-bar would decrease.
(Skip this question)
13.A wildlife reserve contains a population of deer. Suppose that the state’s Department of natural Resources
wants to estimate the total number of deer in the reserve. Two plans are proposed:
Plan I:
a. Select 100 deer at random.
b. Place red tags on the deer and release them into the population.
c. One week later, select 100 deer at random again.
d. Determine the proportion of deer in the new sample with red tags, divide 100 by this proportion.
Plan II:
a. Measure the total area of the wildlife reserve in square miles.
b. Collect all deer in a randomly selected 1 square mile region.
c. Multiply this number by the total number of square miles of the reserve.
On the basis of the information given, which of the two plans should be selected to give the best estimate of the
number of deer in the wildlife reserve?
A. Choose plan I over Plan II.
B. Choose Plan II over Plan I.
C. Choose either plan, since both will provide equally accurate results.
D. Choose neither plan, since neither will provide an accurate estimate.
E. The plans cannot be evaluated from the information given.
14. Karl receives the results on his standardized NEDT scores. The results on his Verbal section indicate that he
finished in the 90th percentile. Which of the following is the best description of what this means?
A.
Karl got 90% of the questions correct.
B.
Karl finished in the top 90% of all those taking the test.
C.
Karl finished in the bottom 90% of all those taking the test.
D.
Ninety percent of all those taking the test scored greater than Karl.
E.
Ninety percent of all those taking the test scored lower than Karl.
15. The following boxplots summarize two data sets, A and B.
(Skip this question)
Which of the following statements must be true?
A. Set A has a higher standard deviation than Set B.
B. Set A has a higher mean than Set B.
C. Set A contains an outlier.
D. Set A has a higher interquartile range than Set B.
E. Set A has more data points than Set B.
16. Which of the following is the best description of a “random sample?”
A.
Each member of the population is equally likely to be chosen in the sample.
B.
Each stratum of the population will be represented in the sample.
C.
The sample contains a large number of values
D.
It is not known ahead of time which values will be chosen in the sample.
E.
The values in the sample do not follow any recognizable patterns.
17. Suppose that a college professor is going to be teaching a course in a large lecture hall. In order to describe
the composition of the students by class, the professor has assigned Freshmen as 1s, Sophmores as 2s, Juniors
as 3s, and Seniors as 4s. If the class consists of 110 Freshmen, 60 Sophmores, 30 Juniors, and 20 Seniors, which
of the following measurements would give the professor the best indicator of the typical students in the class?
A.
Mean
B.
Median
C.
Mode
D.
Range
E.
Standard deviation
18. Suppose that a solid-state company is manufacturing a brand of power strips that is supposed to have a
particular mean wattage. Furthermore, the power strips should be stable, meaning that all the power strips
should have approximately the same wattage. If a sample of 100 power strips is measured, which measurement,
taken from the sample, would give the best indicator of the stability of the brand of power strips?
A.
Mean
B.
Median
C.
Mode
D.
Range
E.
Standard deviation
19. The back-to-back stem-and-leaf plots compare the ages of players with two Minor League baseball teams.
(Skip this question)
Which of the following statements is NOT justified by the data?
A. Waffletown has more players over 30 than Stockton does.
B. The range of ages for both teams is the same.
C. Stockton’s players tend to be slightly younger than Waffletown’s players.
D. Waffletown has a higher median age than Stockton.
E. Stockton has more players in their 20s than Waffletown does.
20. A candidate is seeking election as a delegate for a district representing four counties. The candidate’s staff
wants to take a random sample of 100 voters, in order to estimate the proportion of support the candidate has in
the district. Which of the following methods will best produce a simple random sample?
A.
Use random numbers to select 25 voters from each of the four counties.
B.
Select the first 100 names on a voter registration list for the district.
C.
Use random numbers to select 100 voters from a voter registration list for the district.
D.
From the voter registration list, select every 10th name listed, until 100 are selected.
E.
Send volunteers to street corners and select 100 people from the streets.
21. Suppose that an algebra class is being taught in a large lecture hall. Throughout the course of the semester,
approximately 20% of the students tend to be absent on any given day. The professor wants to design a
simulation to estimate the probabilities of having a five of five randomly selected students being present on a
given day. Which of the following assignments of the digits 0 through 9 would be most appropriate for
modeling the behavior of the students, using a random number table?
A.
Assign “0, 1, 2, 3, 4, 5, 6, and 7” as being absent, and “8 and 9” as being present.
B.
Assign “0, 1, and 2” as being absent, and “3, 4, 5, 6, 7, 8, and 9” as being present.
C.
Assign “0 and 1” as being absent, and “2, 3, 4, 5, 6, 7, 8, and 9” as being present.
D.
Assign “0, 1, 2, 3, 4, and 5” as being present, and “6, 7, 8, and 9” as being absent.
E.
Assign “0, 1, and 2” as being present, and “3, 4, 5, 6, 7, 8, and 9” as being absent.