Matthew is conducting research to learn whether chewing peppermint gum during learning will improve recall if the participants are also chewing peppermint gum when they take a test. Matthew assigns the first 10 people who arrive to his experimental group. He assigns the last 10 people to his control group. What mistake has Matthew already made?

Question

Quizplus · Accepted Answer

Matthew failed to use random assignment when assigning participants to the experimental and control groups. This means that the groups may not be equivalent at the start of the experiment, which could lead to biased results. Additionally, there may be other confounding variables that Matthew did not control for, such as the participants' individual learning abilities or preferences for chewing gum.

Matthew Is Conducting Research to Learn Whether Chewing Peppermint Gum