Question 1

Discuss the main difference between a case-control study and a matched-pairs experiment (other than the fact that one is an observational study and one is an experiment).

Accepted Answer

in a case-control study the researcher does not randomly assign treatments within pairs but is restricted to how they occur naturally (for example right vs left handed).also, not all case-control studies match cases and controls.

Question 2

In order to establish a connection between an explanatory and response variable in an observational study, what is needed?

Accepted Answer

A)  Statistical methods that examine the connection.
B)  A comparison to determine if changes in the explanatory variable are related to changes in the response variable.
C)  Either a or b
D)  You can never establish a connection between an explanatory and a response variable without doing a randomized experiment. C

Question 3

Which of the following is not true about placebos?

Accepted Answer

A)  Placebos can be very effective in producing a response.
B)  Placebos are only useful if the subject is blind as to whether or not they receive one.
C)  Participants assigned a placebo are part of the control group of an experiment.
D)  All of the above are true statements. D

Question 4

A(n) __________ variable is one that attempts to explain or is purported to cause (at least partially) differences in a(n) __________ variable.

Accepted Answer

The answer of A(n) __________ variable is one that attempts...

Question 5

Give an example of an experiment in which it would be unethical to give the control group a placebo.

Accepted Answer

The answer of Give an example of an experiment in...

Question 6

An observational study that follows a group of high school students into the future, recording how many children they have (if any) and at what age(s) they had those children is an example of a(n) __________ study.

Accepted Answer

The answer of An observational study that follows a group...

Question 7

Without random assignment, which of the following can happen?

Accepted Answer

A)  Naturally occurring confounding variables can result in an apparent relationship between the explanatory and response variables.
B)  The results may not be able to be extended to a larger population.
C)  Many people in the study will drop out because they aren't happy with the treatment they were assigned to.This will cause bias in the results.
D)  None of the above.

Question 8

A common mistake made by the media, the general public, and some researchers, is to think that a link between two variables in any study implies that one variable causes the other.Explain what is wrong with this automatic conclusion.

Accepted Answer

The answer of A common mistake made by the media,...

Question 9

Which of the following is a potential complication of observational studies?

Accepted Answer

A)  Confounding variables
B)  The improper conclusion of causation
C)  Improper extension of the results
D)  All of the above

Question 10

One of the complications that can arise with observational studies is __________ variables and the implications of causation.

Accepted Answer

The answer of One of the complications that can arise...

Question 11

For Questions use the following narrative
Narrative: Toy colors
Suppose a toy company wants to know if certain colors are more appealing and attractive to toddlers than others.They decide to measure this by choosing five colors of blocks and making sets of blocks in each of the five colors.Then they found 30 toddlers to participate in the study, and they randomly assigned each toddler a block color.They observed each toddler separately at the same time of the day, and gave them no other toys to play with.They recorded the length of time each toddler played with the blocks, to see if some colors of blocks were played with longer than other colors.All toddlers in the experiment were the same age (2 years old) and an equal number of girls and boys played with each color of blocks.
-{Toy colors narrative} What is the explanatory variable and what is the response variable?

Accepted Answer

The answer of For Questions use the following narrative
Narrative: Toy...

Question 12

How can a researcher try to address the problem of confounding variables when designing an observational study?

Accepted Answer

The answer of How can a researcher try to address...

Question 13

The case-control design has some clear advantages over randomized experiments as well as over other observational studies.Name two of those advantages.

Accepted Answer

The answer of The case-control design has some clear advantages...

Question 14

Which of the following is a potential complication of a poorly designed/conducted experiment?

Accepted Answer

A)  Confounding variables
B)  Interacting variables
C)  Hawthorne effect
D)  All of the above

Question 15

Suppose you come across an experiment or observational study in which a random sample was not used.To what extent can (should) the results be extended to a larger population?

Accepted Answer

The answer of Suppose you come across an experiment or...

Question 16

Suppose you come across an experiment in which random assignment was not used.To what extent will the conclusions of the experiment be affected?

Accepted Answer

The answer of Suppose you come across an experiment in...

Question 17

It is the purpose of what type of study to find out whether one or more explanatory variables are related to a certain disease (for example whether smoking causes lung cancer)?

Accepted Answer

A)  Case-control study
B)  Matched-pairs experiment
C)  Block design
D)  None of the above

Question 18

Which of the following is implemented in an experiment to reduce known sources of natural variability in the response variable, so that differences due to the explanatory variable can be detected more easily?

Accepted Answer

A)  Matched-pairs
B)  Repeated measures
C)  Blocks
D)  All of the above

Question 19

Which of the following studies can result in researchers extending the results inappropriately because the sample doesn't represent the intended population?

Accepted Answer

A)  Studies involving volunteers (self-selected samples) 
B)  Studies involving convenience samples
C)  Case-control studies
D)  All of the above

Question 20

What is the main purpose of using a random sample in a study?

Accepted Answer

The answer of What is the main purpose of using...

Exam 5: Experiments and Observational Studies