The coefficient of correlation, r

• The Coefficient of Correlation (r) is a measure of the strength of the relationship between two variables. It requires interval or ratio-scaled data (variables). 
• It can range from -1.00 to 1.00. 
• Values of -1.00 or 1.00 indicate perfect and strong correlation. 
• Values close to 0.0 indicate weak correlation. 
• Negative values indicate an inverse relationship and positive values indicate a direct relationship