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?