title: Error estimation with matlab
body: <p>I have a data set which I need to fit to two quadratic equation:</p>
  
  <pre><code>f1(x) = a*x + b*x^2
  f2(x) = b*x^2
  </code></pre>
  
  <p>Is there a way to estimate the error where I take into account both the standard error in the measurement and the error in the curve fittig?</p>