Checked content


Description Illustration of linear regression on a data set.
Date 24 June 2007
Source self-made in Gnuplot.
Author Berland

Gnuplot source code

set terminal svg fname "Helvetica" fsize 25
set output "LinearRegression.svg"
set key left
set xtics axis 4.0,0.5
set ytics nomirror 1
set border 2
f(x) = a*x + b
fit f(x) 'randpts' using 1:2 via a,b
set yrange [-0.9:4]
plot 'randpts' with points pointtype 7 pointsize 0.3 title 'Datapoints', \
        f(x) with lines linetype 3 linewidth 3 title 'Regression',  \
        0 with lines linetype -1 notitle

The datafile 'randpts' was made in GNU Octave using the commands

f = fopen('randpts', 'w');
for i=1:200; 
   y=0.2*randn(1) + 3*x + 0.35; 
   fprintf(f, '%g %g\n', x, y); 

(identical code also works in Matlab.)


Public domain This work has been released into the public domain by its author, I, Berland. This applies worldwide.
In some countries this may not be legally possible; if so:
I, Berland grants anyone the right to use this work for any purpose, without any conditions, unless such conditions are required by law.


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