Least-squares fitting of data

About this calculator

This applet allows the user to enter pairs of data -- x, an independent variable; and y, the dependent variable -- and then generates an equation to describe the best "fit" for that data. The applet can generate several types of best-fit equations. It can generate a linear fit, producing the standard y=mx + b equation, where m is the slope and b is the y-intercept (the value of y when x=0). It can also produce a polynomial fit, typically a more accurate equation to describe the data. A polynomial fit with a degree of 3 will produce this equation:
y = c0 + c1*x + c2*x2 +c3*x3

where c0, c1, c2, and c3 are the coefficients. These coefficients (called expansion coefficients by the applet).

Using this calculator

To use this calculator, follow this recipe:

  1. Select the type of fit you want. If you choose a polynomial fit, choose the degree. `
  2. For most fits, leave "Constant" selected.
  3. Click on "Data". A separate window will appear, providing you with a text box. Type or copy your x-y data into the box. The data should be in pairs with a space between the x-value and the y-value. Click on the "Submit" button
  4. Your coefficients will appear in the output window.

Regression Calculator

This applet created by Michel Comeau (http://www3.sympatico.ca/mcomeau/). Applet used by permission of the author. Copyright © 1999 Michel Comeau.