Matthew Is Conducting Research to Determine Whether Drinking Caffeine Will

Multiple Choice

Matthew is conducting research to determine whether drinking caffeine will improve how much information students are able to recall during a study session. Matthew assigns the first 10 people who arrive to his coffee group, the next 10 people to his tea group, and the last 10 people to his control group. What mistake has Matthew already made?

A) he didn't ask if anyone has negative associations with coffee or tea
B) he forgot to ask how much coffee/tea each participant typically drinks in a day
C) he failed to use random assignment
D) his control group did not have enough participants
E) his experimental groups did not have enough participants