title: how do I use pcov in python to get errors for each parameter?
body: <p>I have a code and used curve_fit to fir both Lorentz and gaussin curves to the data.
  I need to get error estimates for each parameter outputted, so have printed both the popt and pcov
  I know the scipy reference guide states how to use pcov matrix to find the errors however this is unclear to me as I am a novice at programming.
  thanks</p>