Correlation is a relationship or dependency that exists between two variables.
If a correlation exists, it is said that the variables are correlated or there is a correlation between them.
Types of Correlation
A positive correlation occurs when an increase in one variable increases the other variable.
The line corresponding to the scatter plot is an increasing line.
A negative correlation occurs when an increase in one variable decreases the other.
The line corresponding to the scatter plot is a decreasing line.
No correlation occurs when there is no linear dependency between the variables.
A perfect correlation occurs when there is a funcional dependency between the variables.
In this case all the points are in a straight line.
A correlation is stronger the closer the points are located to one another on the line.
A correlation is weaker the farther apart the points are located to one another on the line.