The Product Moment Correlation Coefficient

Product Moment Correlation Coefficient (r or ρ) measures strength and direction of linear relationship between two continuous variables.
The method evaluates fit of data points to a straight line on a scatterplot.
Coefficient values range from -1 (perfect negative linear relationship) to 1 (perfect positive linear relationship).
0 indicates no linear association between variables.
Coefficient calculates using a specific formula that involves differences between individual data points and their means, divided by standard deviations of both variables.
Interpretation of the coefficient must be careful as strong correlation doesn’t imply causation, and other factors may influence the relationship.