Simple Linear Regression

TL;DR: Simple linear regression is a technique to relate a response variable to a single predictor variable using a straight line. It uses least squares to find the best slope and intercept.

Abstract: One of the most widely used statistical techniques is simple linear regression. This technique is used to relate a measured response variable, Y, to a single measured predictor (explanatory) variable, X, by means of a straight line. It uses the principle of least squares to come up with values of the “best” slope and intercept for a straight line that approximates the relationship. By means of the example below we motivate the technique, indicate the rationale underlying the calculations and come up with the formulas for the “best” slope and intercept based on the data.