A nurse is interested in whether there is a relationship between daily levels of stress and likelihood of a heart attack. The stress scores (predictor variable) and risk of heart attack values (criterion variable) from a small sample of participants are depicted below.

Stress Score Risk of Heart Attack

(Higher values = more stress) (Higher values = greater risk)

5 8

3 8

2 9

0 7

What is the Pearson's r value?