clf
clear all
clc

% Define the indepedent (x) and dependent (y) variables
x = 0:1:20;
y = 2*x;

% Allocate random error vector
err = zeros(1, length(x));
color = jet(4);

for i = 1:4
  
  % Generate random error vector with mean = zero, var = 1
  err = randn(1, length(x));
  
  subplot(2, 2, i)
  
    % Plot original data (y)
    plot(x, y, '-k', 'markersize', 9)
    hold on
    
    % Plot random data (y + err)
    plot(x, y + i.*err, 'ok', 'markerfacecolor', color(i, 1:end))
    hold on    
  
  % Edit plot
  set(gca, 'fontsize', 16)  
  ylabel('f(x) = y, f(x) = y_{rand}')
  xlabel('x')
  ylim([-10 50])
  hold all
  
end

% Set directory and save figure
cd ~/Documents/Octave;
saveas(gcf, "fig1.eps")