Introduction To StatisticsIntroduction To Statistics

This evaluation will cover the lessons in this unit. It is open book, meaning you can use your
textbook, syllabus, and other course materials. You will need to understand, analyze, and apply the
information you have learned in order to answer the questions correctly. To submit the evaluation by
mail, follow the directions on your Enrollment Information Sheet. To take the evaluation online,
access the online version of your course; use the navigation panel to access the prep page for this
evaluation and follow the directions provided.
Multiple-Choice
Select the response that best completes the statement or answers the question.
_____ 1. On July 7, 2010, The Gallup organization conducted a telephone poll of 1,007 random
adults in all 50 U.S. states and the District of Columbia. They found that 38% strongly
opposed the federal government suing Arizona over their new immigration law. Which
is true?
I. The population of interest is all U.S. adults.
II. 38% is a statistic and not the actual percentage of all U.S. adults who strongly
oppose the lawsuit.
III. This sampling design should provide a reasonably accurate estimate of the actual
percentage of all U.S. adults who strongly oppose this lawsuit.
a. I, II, and III
b. I and II
c. I only
d. II only
_____ 2. A school district has three high schools. The district decides to randomly test high school
students for attention deficit disorder (ADD). The school board creates a list of all of the
students from the three high schools and randomly samples 250 students from that list.
Is this a simple random sample?
a. Yes, because students were chosen at random.
b. No, because we can’t guarantee that there are students from each school in the
sample.
c. Yes, because this method could choose any 250 high school students from
throughout the district.
d. No, because we can’t guarantee that there are students from each high school
grade in the sample.
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_____ 3. A chemistry professor who teaches a large lecture class gives a survey during class about
how he can make the class more interesting. He is hoping he can get more students to
attend his class. This survey method suffers from which of the following?
a. voluntary response bias
b. nonresponse bias
c. response bias
d. undercoverage
Use this information to answer questions 4-7.
A statistics teacher wants to know how her students feel about an introductory statistics
course. She decides to administer a survey to a random sample of students taking the
course. She has several sampling plans to choose from. Name the sampling strategy in
each.
_____ 4. There are four grade levels of students taking the class: freshmen, sophomores, juniors,
and seniors. Randomly select 15 students from each grade level.
a. cluster sampling
b. simple random sampling
c. systematic sampling
d. stratified sampling
_____ 5. Randomly select a grade level (freshmen, sophomores, juniors, and seniors) and survey
every student in that grade level.
a. cluster sampling
b. simple random sampling
c. systematic sampling
d. stratified sampling
_____ 6. Each student has a nine-digit student number. Randomly choose 60 numbers.
a. cluster sampling
b. simple random sampling
c. systematic sampling
d. stratified sampling
_____ 7. Using the class roster, select every fifth student from the list.
a. cluster sampling
b. simple random sampling
c. systematic sampling
d. stratified sampling
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_____ 8. Suppose the state decides to randomly test high school wrestlers for steroid use. There
are 16 teams in the league, and each team has 20 wrestlers. State investigators plan
to test 32 of these athletes by randomly choosing two wrestlers from each team. Is this
a simple random sample?
a. Yes, because the wrestlers were chosen at random.
b. Yes, because each wrestler is equally likely to be chosen.
c. No, because not all possible groups of 32 wrestlers could have been the sample.
d. No, because a random sample of teams was not first chosen.
_____ 9. Which statement about bias is true?
I. Bias results from random variation and will always be present.
II. Bias results from a sampling method likely to produce samples that do not
represent the population.
III. Bias is usually reduced when the sample size is larger.
a. I and III
b. II and III
c. I only
d. II only
_____ 10. The owner of a car dealership planned to develop strategies to increase sales. He hoped
to learn the reasons why many people who visit his car lot do not eventually buy a car
from him. For one month he asked his sales staff to keep a list of the names and
addresses of everyone who came in to test drive a car. At the end of the month he sent
surveys to the people who did not buy a car, asking them why. About one third of them
returned the survey, with 44% of those indicating that they found a lower price
elsewhere. Which is true?
I. The population of interest is all potential car buyers.
II. This survey design suffered from non-response bias.
III. Because it comes from a sample 44% is a parameter, not a statistic.
a. I and II
b. II and III
c. I, II, and III
d. none of the above
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Use this information to answer questions 11-14.
Management at a retail store is concerned about the possibility of drug abuse by people who work
there. They decide to check on the extent of the problem by having a random sample of the
employees undergo a drug test. Several plans for choosing the sample are proposed. Name the
sampling strategy in each.
_____ 11. Randomly select an employee classification and test all the people who work in that
classification – supervisors, full-time clerks, part-time clerks, and maintenance staff.
a. cluster sampling
b. systematic sampling
c. stratified sampling
d. simple random sampling
_____ 12. Choose the fourth person that arrives to work for each shift.
a. cluster sampling
b. systematic sampling
c. stratified sampling
d. simple random sampling
_____ 13. There are four employee classifications: supervisors, full-time clerks, part-time clerks,
and maintenance staff. Randomly select ten people from each category.
a. cluster sampling
b. systematic sampling
c. stratified sampling
d. simple random sampling
_____ 14. Each employee has a three-digit identification number. Randomly choose 40 numbers.
a. cluster sampling
b. systematic sampling
c. stratified sampling
d. simple random sampling
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Use this information to answer questions 15 – 19.
Researchers who wanted to see if drinking grape juice could help people lower their blood pressure
got 120 non-smokers to volunteer for a study. They measured each person’s blood pressure and
then randomly divided the subjects into two groups. One group drank a glass of grape juice every
day while the other did not. After sixty days the researchers measured everyone’s blood pressure
again. They reported that differences in changes in blood pressure between the groups were not
statistically significant.
_____ 15. Was this an experiment or an observational study? Explain.
a. observational; observed 120 non-smokers
b. observational; volunteers caused this study to be biased
c. experimental; treatments were applied
d. experimental; one group/all non-smokers
_____ 16. What is meant by “not statistically significant” in this context?
a. The differences were large since this lasted 60 days.
b. There were not many subjects involved.
c. Only non-smokers were included so this could not be expanded to the general
population.
d. The results were small enough that they could easily be attributed to variability, not
the grape juice.
_____ 17. Why did the researchers randomly assign the subjects to the groups?
a. This equalizes the effects of variables for which were not controlled.
b. This was easier.
c. They could keep track of who was in which group easier.
d. Not everyone liked grape juice.
_____ 18. Why did they have a group that was not drinking grape juice?
a. They did not like grape juice.
b. They needed a control group to compare with the treatment group.
c. This was a placebo since they all needed something.
d. In order for the experiment to be valid, it needed to be confounded.
_____ 19. Why did the researchers study only non-smokers?
a. They wanted to limit the number of subjects in the experiments.
b. That would result in variability.
c. The smokers were used as a control.
d. Smoking tends to affect blood pressure. It might have confounded the results.
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_____ 20. In an experiment the primary purpose of blocking is to reduce ____________.
a. bias
b. randomness
c. variation
d. undercoverage
_____ 21. More dogs are being diagnosed with thyroid problems than have been diagnosed in the
past. A researcher identified 50 puppies without thyroid problems and kept records of
their diets for several years to see if any developed thyroid problems. This is a(n)
____________.
a. prospective study
b. retrospective study
c. randomized experiment
d. survey
_____ 22. Which of the following is not required in an experimental design?
a. control
b. replication
c. randomization
d. blocking
_____ 23. A headline in a local newspaper announced “Video game playing can lead to better
spatial reasoning abilities.” The article reported that a study found “statistically
significant differences” between teens who play video games and teens who do not,
with teens who play video games testing better in spatial reasoning. Do you think the
headline was appropriate? Explain.
a. No, there was no control group.
b. No, this is an observational study which cannot imply causation.
c. Yes, there was a statistically significant difference.
d. Yes, there were two groups, one of which was a control group.
_____ 24. In an experiment, a placebo is used to ____________.
a. speed the rate of the experiment
b. eliminate confounding
c. assist in blinding
d. increase blocking
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_____ 25. A researcher wants to compare the performance of three types of pain relievers in
volunteers suffering from arthritis. Because people of different ages may suffer arthritis
of varying degrees of severity, the subjects are split into two groups: under 60 and over
60. Subjects in each group are randomly assigned to take one of the medications.
Twenty minutes later they rate their levels of pain. This experiment ____________.
a. is completely randomized
b. has one factor (medication) blocked by age
c. has two factors, medication and age
d. has one factor (age) blocked by medication type
_____ 26. Can watching a movie temporarily raise your pulse rate? Researchers have 50
volunteers check their pulse rates. Then they watch an action film, after which they
take check their pulse rates once more. Which aspect of experimentation is present in
this research?
a. a placebo
b. blinding
c. randomization
d. none of these
Use the following information to answer questions 27 – 30.
A study was created to test the effects of jazz on people’s sleep patterns. The hypothesis of the
experiment was that if people listened to jazz music as they fall asleep, they will sleep for longer
periods of time. For the experiment, 2 groups of people were created. One group was placed in a
quiet room where they went to sleep and they were timed on how long they slept. The other group
was placed in a room where jazz music played softly as they began to sleep and played throughout
the night. As each group awoke, their sleep times were monitored.
_____ 27. What is the factor in this case?
a. sleep patterns
b. sleep times
c. jazz played
d. 2 groups of people
_____ 28. What is the response variable?
a. jazz played
b. sleep times
c. 2 groups of people
d. quiet room
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_____ 29. What is the control group?
a. The group with no jazz while sleeping.
b. The group listening to jazz.
c. The group that was given placebos.
d. The group that was blinded.
_____ 30. What is the experimental group?
a. The group in the experiment.
b. The group in the quiet room.
c. The group that was given placebos.
d. The group who listened to jazz while sleeping.
_____ 31. What control was used in this experiment?
Shortly after Ms. Berndt’s cat, Revere, was born, Ms. Berndt realized Revere wasn’t
eating enough. She went to the pet store and bought many different kinds of food and
fed Revere different types every day. Each day she noted the type of food and how
much Revere ate out of his dish. Eventually Revere ate a lot of the CreppyCat brand
food and Ms. Berndt bought that for him from then on. Revere is the best worst cat
ever.
a. Revere was not eating cat food.
b. CreppyCat brand food.
c. Many different kinds of food.
d. There is no control group.
_____ 32. It’s a common belief that people behave strangely when there’s a full moon and that as a
result police and emergency rooms are busier than usual. If you wanted to find out
whether there is any value to this belief, what kind of study would you use and why?
a. experiment; use as a control, those days when there is no full moon
b. experiment; use blinding and don’t tell anyone what you are looking for
c. prospective observational study; find out which days are full moon days and talk
with officers and emergency room personnel
d. retrospective observational study; it is easier to go back three years to find data to
support this belief
_____ 33. A swimsuit manufacturer wants to test the speed of its newly designed swimsuit. The
company designs an experiment by having 6 randomly selected Olympic swimmers
swim as fast as they can in their old suits first, and then swim the event again with the
new, expensive swimsuit. The company will use the difference in times as the
response variable. Which of the following is present in this experiment?
a. blinding
b. an explanatory variable
c. blocking
d. a placebo
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_____ 34. Before drilling for water, many rural homeowners hire a dowser (a person who claims to
sense the presence of underground water using a forked stick). Suppose we wish to
set up an experiment to test one dowser’s ability. We get 20 identical containers, fill
some with water, and ask him to identify which containers have water. The dowser
correctly identifies the contents of 11 out of 20 containers. Is this level of success
statistically significant? Explain.
a. no, he needs to replicate the experiment
b. no, 55% (11/20) is not much better than 50% (10/20)
c. yes, that is better than the mean
d. yes, anything above 0% is great