Question

Does daily exposure to bright light make subjects more alert? A study was conducted in which the daily habits of 60 college students were documented, focusing on how much time they spent in brightly lit rooms or outside on sunny days. After a week, the subjects were given a computer-based alertness test on which they received a score on a 0 to 100 point scale. Their scores were compared with how much time they spent in brightly lit places that week.

Select one or more:

A. The explanatory variable is how much time the students spent in brightly lit places.

B. This study is best described as an observational study.

C. The explanatory variable is the score on the computer-based test.

D. This study is best described as an experiment study.

E. The response variable is the score on the computer-based test.

F. The response variable is how much time the students spent in brightly lit places.

Answer 1

The correct options are:

A. The explanatory variable is how much time the students spent in brightly lit places.

B. This study is best described as an observational study.

E. The response variable is the score on the computer-based test.

Explanation:

We are interested in the studying whether time spent in brightly lit places have any impact on the alertness quotient of the students using alertness scores obtained in the test. So thedependent/response variable would be the scores obtained in alertness test and the explanatory variable would be the time spent in brightly lit areas.

Observational studies are ones where researchers observe the effect of a factor, diagnostic test, treatment or other intervention without trying to change who is or isn’t exposed to it whereas Experimental studies are ones where researchers introduce an intervention and study the effects.

Here we are not changing the group of students and are just observing the effect of an intervention (time spent in brightly lit places) on them. Hence, it is an observational study.