Question

researchers wanted to determine if having a television (tv) in the bedroom is associated with obesity. the researchers administered a questionnaire to 301 parents of adolescents. after analyzing the results, the researchers determined that 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. complete parts (a) through (e) below. 1. (a) the response variable is the body mass index of the adolescents. the explanatory variable is whether the adolescent has a tv in the bedroom or not. what is the explanatory variable? a. the explanatory variable is the body mass index of the adolescents b. the explanatory variable is the number of the adolescents who participate in the study c. the explanatory variable is whether the adolescent has a tv in the bedroom or not d. the explanatory variable is the number of the adolescents who have a tv in their bedroom (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 when the results are separated by socioeconomic status, there are significant differences between each socioeconomic status b. the researchers made an effort to avoid confounding by accounting for potential lurking variables 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. it means that socioeconomic status is an explanatory variable and that including this variable in the study changes the results of the study

Explanation:

Part (a)

The explanatory variable is the factor being tested to see its effect on another variable. Here, researchers test if having a TV in the bedroom affects obesity, so this presence/absence is the explanatory variable.

Part (c)

Lurking variables are unmeasured factors that could influence both the explanatory and response variables. Eating habits and exercise level directly impact body mass index (the response variable) and could correlate with having a TV in the bedroom.

Part (d)

When results remain significant after adjusting for a variable, it means the original association (TV in bedroom and BMI) is not explained by that variable, and the variable is not the driver of the relationship.

Answer:

(a) C. The explanatory variable is whether the adolescent has a TV in the bedroom or not
(c) B. Yes. For example, possible lurking variables might be eating habits and the amount of exercise per week
(d) 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