Noelle investigates whether caffeine increases the endurance of runners. She has two groups of participants run on a treadmill for 15 minutes. One group drinks regular coffee before running, while the...

Extracted text: Noelle investigates whether caffeine increases the endurance of runners. She has two groups of participants run on a treadmill for 15 minutes. One group drinks regular coffee before running, while the other group drinks decaffeinated coffee before running. The group that drinks decaffeinated coffee is the control group. confederate group. confound group. experimental group.