## Correlation analysis

In probability theory and statistics, correlation also called correlation coefficient indicates the strength and direction of a linear relationship between two random variables.

Correlation is a measure of association between two variables. The variables are not designated as dependent or independent.

The value of a correlation coefficient can vary from minus one to plus one. A minus one indicates a perfect negative correlation, while a plus one indicates a perfect positive correlation. A correlation of zero means there is no relationship between the two variables. When there is a negative correlation between two variables, as the value of one variable increases, the value of the other variable decreases, and vice versa. In other words, for a negative correlation, the variables work opposite each other. When there is a positive correlation between two variables, as the value of one variable increases, the value of the other variable also increases. The variables move together. 