With the wide usage of Statistical Analysis Computer Applications and Statistical Graphing Calculators, curve-fitting is more popular than when the method was done "by-hand."  This page explains the general concept of the procedure.  Details are given for special cases in other Regression Tutorials.

Procedure Overview

1. Given paired numerical variables, decide which variable is independent (x) and which is dependent (y). 
2. Draw a scatterplot of the data.
3. Examine the scatterplot to determine the basic shape of the curve.  For example, the shape might be 

   • Linear
   • Quadratic
   • Cubic
   • Quartic
   • Exponential
   • Logarithmic
   • Sinusoidal

4. Once the best basic shape is determined you can approximate the curve "by-hand" using algebraic methods.  However, you may prefer to use a calculator with regression features or a statistical computer application to find an equation to represent the relationship.  The links below provide the procedures available for curve fitting with Excel and Minitab.

Note:  Other Regression Tutorials provide details and formulas for by-hand procedures.  

Learn the Curve Fitting Procedures

Curvefitting Menu

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