A linear relationship (or linear association) is a statistical term used to describe the directly proportional relationship between a variable and a constant.

Exponential growth is a pattern of data that shows greater increases with passing time, creating the curve of an exponential function.

George Eads, Marc Nerlove, William Raduchel, A Long-Run Cost Function for the Local Service Airline Industry: An Experiment in Non-Linear Estimation, The Review of Economics and Statistics, Vol. 51, ...