what is a linear relationship 
a linear relationship or linear association is a statistical term used to describe a straight line relationship between two variables linear relationships can be expressed either in a graphical format where the variable and the constant are connected via a straight line or in a mathematical format where the independent variable is multiplied by the slope coefficient and added by a constant which determines the dependent variable a linear relationship may be contrasted with a polynomial or non linear curved relationship formula for a linear relationshipmathematically a linear relationship is one that satisfies the equation y m x b where m slope b y intercept begin aligned y mx b textbf where m text slope b text y intercept end aligned y mx bwhere m slopeb y intercept in this equation x and y are two variables that are related by the parameters m and b graphically y mx b plots in the x y plane as a line with slope m and y intercept b the y intercept b is simply the value of y when x 0 the slope m is calculated from any two individual points x1 y1 and x2 y2 as m y 2 y 1 x 2 x 1 m frac y 2 y 1 x 2 x 1 m x2 x1 y2 y1 