A physical therapist is planning a research study investigating the relationship between plantar flexor strength and gait speed. Gait speed will be measured with motion analysis equipment, and strength will be measured with a hand-held dynamometer. What type of statistical test would be used to determine if there was a linear association/relationship between gait speed and plantar flexor strength?

a) chi square
b) independent t test
c) Pearson r
d) repeated measures analysis of variance