GraphDraw

Results of fitting


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Results windows

When a fit process is chosen from the data input menu, e.g. polynomial or linear least squares, then a new window will open showing the results of the fit. The linear least squares and parabola result windows are shown below as examples.

  

Whichever fit is chosen, the corresponding window will open showing the calculated parameters for the fitted equation.

All these windows have one thing in common - the buttons at the foot of the window labelled Graph and Save.

Graph

Clicking on Graph will open a graph window showing the data points and the line calculated from the fitted equation on suitably scaled axes. The style of the graph will follow the settings in Choices, but can be modified easily if necessary. See the Graph and Graph layout options pages for more information.

Save

Clicking on Save will produce a Save as dialogue, from which a text file can be saved (or loaded into a suitable application). This text file contains the information produced by the fitting process. In addition, depending on the actual fit carried out, it may also list the point data as entered and as calculated from the fit equation, etc.

An example from a linear fit is shown below (some data points have been omitted from the full data set).

Results of best line fit
========================

                      Slope = 3.54402
        Intercept on y axis = -48.4203
    Correlation coefficient = 0.99944
    Standard error of slope = 0.0395555
Standard error of intercept = 1.39883
      Sum of errors squared = 18.0605

       Error in Y value for each point
       ===============================

       X obs       Y obs      Y calc       Error
       ----        -----      ------       -----

          16           9     8.28402    0.715977
          19          18     18.9161   -0.916076
          29          53     54.3563    -1.35625
          33          69     68.5323    0.467678
          36          80     79.1644    0.835625
          41          97     96.8845    0.115537
          45         113     111.061     1.93947
          48         123     121.693     1.30741
          52         133     135.869    -2.86866

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GraphDraw is © Chris Johnson, 2014
Email:chris@chris-johnson.org.uk

This document last modified on 15th August 2015