Apr. 22

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Apr. 22

• Stat 100

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Final Wednesday April 24

• About 40 or so multiple choice questions
• Comprehensive
• Study the midterms
• Copies and answers are at the course web site

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Exam 4 , White 5 Yellow 17
5. In an observational study, confounding
means B. That the effect of the explanatory
variable on the response variable changes for
different categories of a third variable. D. That
the effect of the explanatory variable on the
response variable can't be separated from the
effect of other variables on the response.
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Exam 4, White 13 Yellow 1
13. Eighty individuals who wished to lose weight
were randomly divided into two groups of 40. One
group was given an exercise program to follow
while the other group was given a special diet.
After three months, the researcher compared mean
weight losses in the two groups. What type of
study is this? D. Randomized experiment
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Exam 4, White 23 Yellow 23
23. Twenty students each are asked to randomly
pick either the letter S or the letter Q.
Fifteen of the students picked S. The null
hypothesis is that the picking is random which
means both letters had an equal chance to be
picked. Which choice describes a P-value for
testing the significance of the observed data?
B. The probability that 15 or more students
would pick S if picking is random
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Exam 4, White 27 Yellow 14
27. Which of the following time series is most
likely to show a seasonal component if it were
graphed? A. annual sales of gardening tools in
the United States D. monthly highway travel
in Pennsylvania
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Exam 4, White 28 Yellow 3
28. At the end of a newspaper article about a new
medication for the relief of cold and flu
symptoms, the researcher is quoted as saying that
there was a 1 in 3 probability that the observed
difference between the medication and a placebo
could have occurred due to chance luck. In
statistical terms, the researcher is saying the
difference between the medication and the placebo
was ____. B. not significant
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Exam 4, White 30 Yellow 19
30. An experiment is usually preferred to an
observational study because ___. A It is easier
to collect data from an experiment than it is
from an observational study. C. One can draw a
cause and effect conclusion in an experiment but
not in an observational study.
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From Exam 3
5. A small college wants to know what percentage
of its current 1,600 students wants a switch to a
quarter system. Every student in the college is
polled with a question that's attached to the
course registration form. What's the margin of
error for the poll? A. 0 B.
2.5 C. 5
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From Exam 3
6. Which of the following is the principal
benefit of increasing the sample size of a
survey? A. A larger sample size decreases the
biasB. A large sample size decreases the margin
of errorC. A large sample size improves the
statistical validityD. All of choices A,B, and
C are true
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From Exam 2
10. The relative risk of an automobile accident
when driving on a Friday night is 50 for drivers
who drink and drive. Suppose the risk of an
accident for those who dont drink and drive
2/5000. For those who drink and drive, what is
the risk of an accident on a Friday night.?A.
1/250000 B. 100/5000 C. 52/5000
D. 50/5000
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From Exam 2
19. Suppose an equation has been developed that
relates college GPA to verbal SAT? What
statistical technique has been used? A.
Regression B. Chi-square C.
Correlation D. Expected Value
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From Exam 2
Questions 21 and 22. Suppose the risk of high
blood pressure is 15 for smokers and 10 for
non-smokers. 21. Whats the percent increase in
risk of high blood pressure for smokers compared
to non-smokers? B. 50 22. For non-smokers,
what are the odds of having high blood
pressure? C. 1 to 9
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From Exam 2
29. Molly and Amy each randomly and
independently pick a number between 1 and 10.
Assume for each, that all numbers are equally
likely. What is the probability that they both
pick the same number? A. (1)(1/10)
B. (1/10)(1/10) C.
(1/10)(1/10) D. 0
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From Exam 1
17. An investigator is doing an observational
study to determine whether baldness is an
indicator of heart disease in men. He measure the
baldness pattern of 200 men with heart disease
and also does this for 200 other men without
heart disease He selected these other men so that
they were about the same age as the heart disease
patients. What type of study design is this?
A. Case Control B. Randomized C.
Double Blind D. Blocked Experiment
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From Exam 1
15. A list of four test scores is 80, 60, 100,
70. What is the median score? A. 77.5
B. 60 C. 80 D. 75
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From Exam 1

• 26. Eighty individuals who wished to lose weight
  were randomly divided into two groups of forty.
  Researchers give one group an exercise program to
  follow, while the other group is given a special
  diet. What type of study is this?
• . Observational B. Case control C.
  Matched pairs study D. Randomized experiment

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From Exam 1
31. What is the benefit of using randomization
in an experiment? A. the placebo effect is
eliminated B. the Hawthorne effect is
eliminated C. It guarantees ecological
validity D. the risk of confounding is reduced