meansquarederrorline;               % generate data
p0 = [2.0, 1.0];
pest = lsqcurvefit(@powerLaw, p0, x, y)

hold on;
% generate x-values for plottig the fit:
xx = min(x):0.01:max(x);
yy = powerLaw(xx, pest);
plot(xx, yy);                       % plot fit
plot(x, y, 'o');                    % plot original data
xlabel('Size [m]');
ylabel('Weight [kg]');
legend('fit', 'data', 'location', 'northwest');