STATS
Last 4 ID____________________
Quiz on Review
Period______
Use for questions 1 - 3. A researcher at The Ohio State University believes that a certain component of ant venom can
be used to lessen the amount of swelling in the knuckles of people suffering from arthritis. The ant venom treatment
has been made into a capsule form that can be swallowed.
1. Draw an experiment diagram to investigate whether this new ant venom capsule, when taken orally each day for
one week, causes a lower degree of swelling in arthritis sufferers compared to a traditional treatment of ibuprofen.
(You may suppose that 200 people suffering from arthritis have already volunteered to be experimental subjects.)
200 arthritis
sufferers
randomly
assigned to 2
groups
100--ant venom
capsule
100--control
groupibuprofen
Measure and
compare
degree of
swelling
2 Multiple Choice. Identify the explanatory variable and the response variable in your experiment.
a. Explanatory: type of drug capsule; Response: amount of swelling
b. Explanatory: arthritis; Response: amount of ant venom
c. Explanatory: ant venom; Response: ibuprofen
d. Explanatory: ibuprofen; Response: volunteers
3. Multiple Choice. What type of experimental design is this?
a. completely randomized b. matched pairs
c. block
d. none of the above
4. Multiple Choice. Suzy is a student in Ms. Blanch’s class, but her friend Eleanor is in Mr. Smith’s class. They are
arguing over who the better teacher is. Suzy proposes an experiment in which one group of students will have Ms.
Blanch for nine weeks, and then Mr. Smith for nine weeks. The other group will have Mr. Smith for the first nine
weeks, and then switch to having Ms. Blanch. Then they will compare which students did better. What type of design
is this?
a. completely randomized
b. matched pairs
c. block
d. none of the above
Use for questions 5-7. Does the cocoa butter in chocolate raise cholesterol levels? Previous studies have found that
people’s current cholesterol levels – high, medium, or low – can affect how much their cholesterol level changes over
the course of an experiment. You may assume that 200 volunteers – 50 with high cholesterol, 100 with medium
cholesterol, and 50 with low cholesterol have agreed to digest pills on a daily basis for two weeks.
5. Multiple Choice. What type of experimental design would be best used for this situation?
a. completely randomized
b. matched pairs
c. block
d. none of the above
6. Multiple Choice. What could be used as the control element in this design?
a. current cholesterol level
b. the low cholesterol group
c. exercise
d. placebo pill with no cocoa butter
7. Describe one way the subjects could be assigned one of two treatments for this experiment. Be specific so that
someone could also do it in the same manner.
50 with high cholesterol will be randomly assigned to 2 groups of 25, one group will get pill with cocoa butter
and one group will get placebo pill with no cocoa butter
100 with medium cholesterol will be randomly assigned to 2 groups of 50, one group will get pill with cocoa
butter and one group will get placebo pill with no cocoa butter
50 with low cholesterol will be randomly assigned to 2 groups of 25, one group will get pill with cocoa butter
and one group will get placebo pill with no cocoa butter
Use for questions 8-9. A health worker is interested in determining if Omega-3 fish oil can help reduce cholesterol in
adults. She obtains permission to examine the health records of 200 people in a large medical clinic and classifies
them as to whether or not they take omega-3 fish oil. She also obtains their latest cholesterol readings and finds that
the mean cholesterol reading for those who are taking omega-3 fish oil is 18 points lower than the mean for the
group not taking omega-3 fish oil.
8. Multiple Choice. Which of the following best describes why overall diet may be a possible confounding variable in
this study?
a. Perhaps the people taking omega-3 fish oil have a better overall diet than the group not taking the fish oil so their
cholesterol is lower because of the diet not the fish oil
b. Everyone has a different overall diet, so you can’t tell how diet might affect their cholesterol levels
c. Maybe some of the people have a better overall diet than others so the fish oil could have a different effect on
their cholesterol level than the others
d. Overall diet is not a possible confounding variable in this study.
9. Multiple Choice. Should we conclude from this study that taking omega-3 fish oil will lower your cholesterol? Why
or why not?
a. Yes, the omega -3 group had a lower cholesterol level, so taking it lowers your cholesterol.
b. No, this is an observational study.
c. No, there are possible confounding variables that might lead to the lower cholesterol level.
d. No, she should conduct an experiment randomly assigning omega-3 fish oil to half of her subjects.
e. Answers b, c, and d are all correct.