A researcher is examining the relationship between stress levels and performance on a test of
cognitive performance. She hypothesizes that stress levels lead to increase in performance to a
point, and then increased stress decreases performance. She tests ten participants, who have
the following levels of stress: 10.94, 12.76, 7.62, 8.17, 7.83, 12.22, 9.23, 11.17, 11.88, and 8.18.
When she tests their levels of mental performance, she finds the following cognitive
performance scores (listed in the same participant order as above): 5.24, 4.64, 4.68, 5.04, 4.17,
6.20, 4.54, 6.55, 5.79, and 3.17.
a. Name the Independent variable (IV) and the Dependent variable (DV).
b. Choose and perform the most suitable analysis to test the above hypothesis.
c. Create a graph to demonstrate the relationship between the two variables.
d. Report and explain the results.
