Dr. Cikara is a psychologist at Harvard University Psychology Department interested in understanding the impact of a sense of control on stress in humans. She brings in students from around campus and gives them a number of choices (increasing sense of control) before exposing them to a very difficult math test. She brings in another group of students and does not give them any choices before giving them the math test. She uses the scores earned by the two groups to see if those students given choices before the test do better than the students who did not get choices. laboratory observation O case history naturalistic observation O psychological test O experiment survey