Researchers wanted to determine if having a

television (TV)

in the bedroom is associated with obesity. The researchers administered a questionnaire to

372

twelve-year-old adolescents. After analyzing the results, the researchers determined that the body mass index of the adolescents who had aTV in their bedroom was significantly higher than that of the adolescents who did not have a TV in their bedroom

(b) What is the response variable in the study? Is the response variable qualitative or quantitative? What is the explanatory variable?

What is the response variable in the study? Is the response variable qualitative or quantitative?

A.

The response variable is the number of the adolescents who participate in the study. The response variable is quantitative.

B.

The response variable is the number of the adolescents who have a
TV
in their bedroom. The response variable is quantitative.

C.

The response variable is the body mass index of the adolescents. The response variable is quantitative.

D.

The response variable is whether the adolescent has a
TV
in the bedroom or not. The response variable is qualitative.

What is the explanatory variable?

A.

The explanatory variable is the number of the adolescents who have a
TV
in their bedroom.

B.

The explanatory variable is the number of the adolescents who participate in the study.

C.

The explanatory variable is the body mass index of the adolescents.

D.

The explanatory variable is whether the adolescent has a
TV
in the bedroom or not.

(c) Can you think of any lurking variables that may affect the results of the study?

A.

No, there are no lurking variables in this study.

B.

Yes. For example, possible lurking variables might be
eating
habits and the amount of exercise per week.

C.

Yes. For example, a possible lurking variable might be the age of the individual.

D.

There is not enough information to answer this question.

(d) In the report, the researchers stated, "These results remain significant after adjustment for socioeconomic status." What does this mean?

A.

It means that socioeconomic status is an explanatory variable and that including this variable in the study changes the results of the study.

B.

It means that when the results are separated by socioeconomic status, there are significant differences between each socioeconomic status.

C.

It means that socioeconomic status is not an explanatory variable and that including this variable in the study does not change the results of the study.

D.

The researchers made an effort to avoid confounding by accounting for potential lurking variables.

(e) Does a
television
in the bedroom cause a higher body mass index? Explain.

A.

No. The results state that a
TV
in the bedroom causes a higher body mass index for twelve-year-old adolescents, but the conclusion cannot be made that it causes a high body mass index for all people.

B.

No. It can only be said that a
TV
in the bedroom and obesity are associated because the body mass index of the adolescents who had a
TV
in their bedroom was significantly higher than that of the adolescents who did not have a
TV
in their bedroom.

C.

Yes. A
TV
in the bedroom is associated with obesity because the body mass index of the adolescents who had a
TV
in their bedroom was significantly higher than that of the adolescents who did not have a
TV
in their bedroom.

D.

Yes. A
TV
in the bedroom causes obesity because the body mass index of the adolescents who had a
TV
in their bedroom was significantly higher than that of the adolescents who did not have a
TV
in their bedroom.

Question

Researchers wanted to determine if having a

television (TV)

in the bedroom is associated with obesity. The researchers administered a questionnaire to

372

twelve-year-old adolescents. After analyzing the results, the researchers determined that the body mass index of the adolescents who had aTV in their bedroom was significantly higher than that of the adolescents who did not have a TV in their bedroom

(b) What is the response variable in the study? Is the response variable qualitative or quantitative? What is the explanatory variable?

What is the response variable in the study? Is the response variable qualitative or quantitative?

A.

The response variable is the number of the adolescents who participate in the study. The response variable is quantitative.

B.

The response variable is the number of the adolescents who have a

TV

in their bedroom. The response variable is quantitative.

C.

The response variable is the body mass index of the adolescents. The response variable is quantitative.

D.

The response variable is whether the adolescent has a

TV

in the bedroom or not. The response variable is qualitative.

What is the explanatory variable?

A.

The explanatory variable is the number of the adolescents who have a

TV

in their bedroom.

B.

The explanatory variable is the number of the adolescents who participate in the study.

C.

The explanatory variable is the body mass index of the adolescents.

D.

The explanatory variable is whether the adolescent has a

TV

in the bedroom or not.

(c) Can you think of any lurking variables that may affect the results of the study?

A.

No, there are no lurking variables in this study.

B.

Yes. For example, possible lurking variables might be

eating

habits and the amount of exercise per week.

C.

Yes. For example, a possible lurking variable might be the age of the individual.

D.

There is not enough information to answer this question.

(d) In the report, the researchers stated, "These results remain significant after adjustment for socioeconomic status." What does this mean?

A.

It means that socioeconomic status is an explanatory variable and that including this variable in the study changes the results of the study.

B.

It means that when the results are separated by socioeconomic status, there are significant differences between each socioeconomic status.

C.

It means that socioeconomic status is not an explanatory variable and that including this variable in the study does not change the results of the study.

D.

The researchers made an effort to avoid confounding by accounting for potential lurking variables.

(e) Does a

television

in the bedroom cause a higher body mass index? Explain.

A.

No. The results state that a

TV

in the bedroom causes a higher body mass index for twelve-year-old adolescents, but the conclusion cannot be made that it causes a high body mass index for all people.

B.

No. It can only be said that a

TV

in the bedroom and obesity are associated because the body mass index of the adolescents who had a

TV

in their bedroom was significantly higher than that of the adolescents who did not have a

TV

in their bedroom.

C.

Yes. A

TV

in the bedroom is associated with obesity because the body mass index of the adolescents who had a

TV

in their bedroom was significantly higher than that of the adolescents who did not have a

TV

in their bedroom.

D.

Yes. A

TV

in the bedroom causes obesity because the body mass index of the adolescents who had a

TV

in their bedroom was significantly higher than that of the adolescents who did not have a

TV

in their bedroom.

Accepted Answer

This is an observational study because the researchers observe the behavior of the individuals in…