Regression is a functional relation between two correlated variables.
We have previously studied that correlation coefficient shows us whether the correlation between two variables is positive or negative. However, the correlation coefficient fails to provide the expected value of one variable for the given value of the other variable. For this, it is necessary to use the concept of regression.
The literal meaning of regression is 'to avert' or 'return to the mean value'. The term regression was first used by a statistician Sir Francis Galton during his study of human inheritance.