A college chemistry teacher wants to know whether taking a practice exam will help her students score higher on their final exam. She
randomly selects 50 students from among the four sections of
Introductory Chemistry that she teaches. Then she randomly divides
them into two groups of 25 students each. Group A will take a practice
exam, and group B will not take a practice exam. After all 50 students
take their final exam, she will compare their results.
Which of these are the treatments in this experiment?
A. Taking a morning chemistry class and taking an afternoon
chemistry class
B. Having taken high school chemistry and not having taken high
school chemistry
C. Being one of the 50 students selected and not being one of the 50
students selected
D. Taking a practice exam and not taking a practice exam