% first plot a straight line:

y = inline ( 'x + 10')
fplot (y, [0, 110, 0, 120]) % This is a traight line with slope 1, and y-intercept 10

hold on;     % hold on to the picture so we can have sxeveral plots on the screen
             % at the same time.

xp = [100]; % define an array of length 100
yp = [100]; % ditto
r  = 5 .* rand(100) - 2.5; % define an array of length 100 whose entries are
                           % between -2.5 and +2.5

% construct a function which is a straight line y (x) plus a
% random component (white noise):

for i = 1:100
  xp (i) = i;
  yp (i) = y (xp(i)) + r(i);
end

plot (xp, yp, 'Color', 'red') % plot the result.