Question 1

Which of the following statements about case-control studies is false?

Accepted Answer

The statement "Any controls that are selected will improve the quality of the results of the study" is false. The quality of the results depends on the appropriate selection and matching of controls to cases, as well as other aspects of the study design and execution. Choosing inappropriate controls can actually lead to biased or misleading results.

Question 2

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

Accepted Answer

Both statistical methods and a comparison between changes in the explanatory and response variables are necessary to establish a connection between them in an observational study. However, it is important to note that randomized experiments can provide stronger evidence of a causal relationship between variables.

Question 3

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

The answer of Discuss the main difference between a case-control...

Question 4

Which of the following is not a type of observational study?

Accepted Answer

Case-control, retrospective, and prospective studies are all types of observational studies commonly used in medical research. However, introspective study is not a recognized type of observational study.

Question 5

Which of the following influences on the experimental units can bias the results of an experiment?

Accepted Answer

All of the listed influences on experimental units can bias the results of an experiment. The placebo effect is when the subject's belief in the treatment causes them to show an improvement in symptoms, regardless of the actual effectiveness of the treatment. The Hawthorne effect is when the subjects' behavior changes due to the awareness of being studied, rather than the treatment being tested. Not being blinded can introduce bias if the researchers or subjects have prior expectations or knowledge that could influence the results. Therefore, D, all of the above, is the best choice.

Question 6

Discuss the biggest problem with using volunteers to participate in an experiment.

Accepted Answer

The answer of Discuss the biggest problem with using volunteers...

Question 7

If the experimental units as a group do not represent the intended population, the researcher cannot __________ the results from the experiment to the intended population.

Accepted Answer

The answer of If the experimental units as a group...

Question 8

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

This type of study is known as a case-control study. It involves comparing individuals who have the disease (cases) with individuals who do not have the disease (controls) in terms of their exposure to the explanatory variable(s) of interest (in this example, smoking). The goal is to determine whether there is a significant association between the explanatory variable and the disease outcome. Matched-pairs experiments and block designs are typically used in experimental studies, rather than observational studies like case-control studies.

Question 9

Which of the following statements is true?

Accepted Answer

All of the statements are true. A placebo can have a strong effect on experimental outcomes because of the power of suggestion known as the placebo effect. Participants in an experiment may alter their responses because they are aware they are being studied, a phenomenon called the experimenter effect. Lastly, an experimenter's expectations can lead to bias in their interpretation of results, known as the observer-expectancy effect.

Question 10

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 11

A group of volunteers is clearly not a random sample from the population, yet volunteers are often used in experiments.Explain why.

Accepted Answer

The answer of A group of volunteers is clearly not...

Question 12

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 13

Name one disadvantage and one advantage of an observational study over an experiment.

Accepted Answer

The answer of Name one disadvantage and one advantage of...

Question 14

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 15

Which of the following describes an experiment with little or no ecological validity?

Accepted Answer

An experiment with little or no ecological validity is one where the variables are measured in an artificial setting that does not accurately reflect the real world. This means that the results of the experiment cannot be applied to real-world situations with confidence. Harmful experiments and experiments with no ecological benefits are concerns, but do not necessarily relate to ecological validity.

Question 16

Which type of observational study gives you better quality data, a retrospective study or a prospective study, and why?

Accepted Answer

The answer of Which type of observational study gives you...

Question 17

In an experiment to see if a certain new drug can prevent a second heart attack, other drugs that the experimental units may or may not be taking already for heart related illnesses would be considered to be __________ variables.

Accepted Answer

The answer of In an experiment to see if a...

Question 18

An observational study that asks participants to recall their first childhood memory is a(n) __________ study.

Accepted Answer

The answer of An observational study that asks participants to...

Question 19

Name two ways in which an experimenter can bias the results in a poorly designed experiment.

Accepted Answer

The answer of Name two ways in which an experimenter...

Question 20

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

Accepted Answer

All of the options listed are potential complications of a poorly designed/conducted experiment. Confounding variables refer to variables that impact the outcome of the experiment but are not being directly measured or controlled, interacting variables refer to variables that impact the outcome of the experiment in combination with one another, and the Hawthorne effect refers to the phenomenon where participants modify their behavior because they know they are being observed. A poorly designed/conducted experiment can lead to any or all of these complications, which can ultimately impact the validity of the results.

Quiz 5: Experiments and Observational Studies