Question

A group of scientists is conducting an experiment on the effects of media on children. They randomly select 100 children and randomly assign each child

to one of four treatment groups. Each treatment group has a specific amount of screen time during a one-week time frame. The first group has no
screen time, the second group has two hours of screen time, the third group has four hours of screen time, and the fourth group has six hours of screen
time.
After the first week, the scientists conduct the same experiment, with the same subject groups, for three more weeks so that each group experiences
each of the four treatments.
Which statements about this study are true?

A. This study uses blinding.

B. This study uses a control group.

C. This study uses blocking.

D. This study uses random sampling.

E. This study uses a repeated measures design.

Answer 1

The correct statements about this study are:

B. This study uses a control group.

E. This study uses a repeated measures design.

A control group is a group that does not receive any treatment or intervention. In this study, the first group that has no screen time serves as the control group. By comparing the outcomes of the other treatment groups to the control group, the scientists can determine the effects of different amounts of screen time on children.

A repeated measures design means that each participant in the study experiences all of the treatments. In this study, each group of children experiences each of the four treatments over the course of the four weeks. This allows the scientists to compare the effects of different amounts of screen time within the same group of children, which increases the reliability of the results.