Question 1

Which of the following best describes the type of study conducted in the 'Television in the Bedroom' example, where researchers questioned 537 twelve-year-old adolescents about TV presence in their bedroom and compared their BMI levels?

Accepted Answer

An observational study, because the researchers only observed and recorded existing conditions without intervention.

Question 2

In the 'Television in the Bedroom' study, what is the explanatory variable?

Accepted Answer

The presence of a TV in the bedroom.

Question 3

What is the response variable in the 'Television in the Bedroom' study?

Accepted Answer

The BMI (Body Mass Index) of the adolescent.

Question 4

Which of the following statements is most accurate regarding the results of the 'Television in the Bedroom' study?

Accepted Answer

There is an association between having a TV in the bedroom and higher BMI, but causation cannot be claimed.

Question 5

Suppose researchers adjusted for socioeconomic status in the 'Television in the Bedroom' study and still found a significant association. What does this adjustment mean?

Accepted Answer

Socioeconomic status is no longer a potential confounding variable in the analysis.

Question 6

Which of the following could be a lurking variable in the 'Television in the Bedroom' study?

Accepted Answer

The adolescent's physical activity level, which was not measured.

Question 7

Why can't the researchers claim that having a TV in the bedroom causes higher BMI based on this study?

Accepted Answer

Because the study was observational and did not control all possible confounding and lurking variables.

Question 8

Which of the following best defines a lurking variable in the context of the 'Television in the Bedroom' study?

Accepted Answer

A variable not considered in the study that affects both the explanatory and response variables.

Question 9

If a confounding variable is present in a study, what is the main consequence?

Accepted Answer

The effects of two or more explanatory variables cannot be separated.

Question 10

A researcher wants to test if a new exercise program reduces BMI in adolescents. Which study design would allow the researcher to claim causation if properly conducted?

Accepted Answer

A designed experiment where participants are randomly assigned to either the exercise program or a control group.

Question 11

Which of the following is a key reason why observational studies are sometimes preferred over designed experiments?

Accepted Answer

It may be unethical or impractical to manipulate the explanatory variable in a designed experiment.

Question 12

In the context of the 'Television in the Bedroom' study, which of the following best describes the association found?

Accepted Answer

There is a statistically significant association between having a TV in the bedroom and higher BMI.

Question 13

Which of the following statements about confounding and lurking variables is correct?

Accepted Answer

A lurking variable is not considered in the study but affects both the explanatory and response variables.

Question 14

Suppose a study finds that children with TVs in their bedrooms have higher BMI, but after adjusting for physical activity, the association disappears. What does this suggest?

Accepted Answer

Physical activity was a confounding variable.

Question 15

Which of the following is the correct formula for calculating Body Mass Index (BMI)?

Accepted Answer

$$BMI = \frac{weight\ (kg)}{$$height^2$$\ (m^2$)}$$

Observational Studies vs Designed Experiments: Data Collection and Confounding

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