CORRELATION

Correlation is a statistical method used to determine whether a relationship between variables exists.

DIFFERENT TYPES OF CORRELATION

• Positive Correlation: If x and y have a strong positive linear correlation, r is close to ¬¬+1. An r value of exactly -1 indicates a perfect positive fit.
• Negative Correlation: If x and y have a strong negative linear correlation, r is close to -1. An r value of exactly -1 indicates a perfect negative fit.
• No Correlation: If there is no linear correlation or weak linear correlation, r is close to 0.
• Perfect Correlation: If  1 occurs only when the data points all lie exactly on a straight line. If r = +1, the slope of this line is positive. If r = -1, the slope of this line is negative.

A correlation greater than 0.8 is generally described as strong, whereas a correlation less than 0.5 is generally described as weak.