A beauty product company conducts a study to test the effectiveness of a new shampoo to control split ends. One hundred subjects have volunteered to take part in the study, and will be split into a treatment group and a placebo group. The study leader will assign the subjects to the groups randomly using slips of paper. Which reason identifies why randomization is important?
Answer
A
It is important to make sure that groups have 50 people each.
B
It is important to make sure that the first 50 people to volunteer are not all in the same group.
C
It is important to make sure that people who do not currently have many split ends are placed in the placebo group.
D
It is important that subject characteristics such as hair length, hair color, and gender are distributed equally among the treatment groups.