Researchers interested in the effects of caffeine on anxiety have randomly assigned participants to one of two conditions in a study—the nocaffeine condition or the caffeine condition. After drinking two cups of either regular or decaffeinated coffee, participants will take an anxiety inventory.
a. What is the independent variable in this study?
b. What is the dependent variable in this study?
c. Identify the control and experimental groups in this study.
d. Is the independent variable manipulated, or is it a subject variable?