Diaz Conducts a Decision-Making Experiment to Determine If People Reason

Multiple Choice

Diaz conducts a decision-making experiment to determine if people reason more logically when they have more time to decide.All the participants who are under 40 are allowed 15 minutes to reach a decision about a problem; all the participants who are over 40 are allowed 20 minutes to reach a decision about the same problem.Diaz has a problem with his experimental design because

A) there are two control groups and no experimental group.
B) the time allowed for the decision is confounded with the independent variable.
C) there is no dependent variable in the experiment.
D) the age of the participants is confounded with the independent variable.