ABSTRACT
There are many occasions in engineering that require an experiment to determine the behavior of a particular phenomenon. The experiment may produce a set of data points that represents a relationship between the variables involved in the phenomenon. This chapter expresses this relationship analytically for further analysis. A mathematical expression that describes the data is called an approximating function. There are two approaches to determining an approximating function: the approximating function passes through all data points and the approximating function graphs as a smooth curve. MATLAB® calls curve fitting with a polynomial by the name Polynomial Regression. The approximating curve will generally not pass through all the data points, but one seeks to minimize the resulting error in order to get the best fit. A plot of the data on linear, semilog or log-log graphic paper can often suggest an appropriate form for the approximating function.
