es are expected to be outside the N% interval. Intervals from
the sampling method can be asymmetric, and may perform better in the
presence of strong correlations, but may take (much) longer to
calculate. The sampling method also assumes that the uncertainty on the
parameters can modeled by a multi-variate Gaussian distribution.
<br><br>
A complete example is provided in a new tutorial macro <tt>rf610_visualerror.C</tt>,
the output of which is shown below.
<br><br>
   <img src="roofit_524_visualerror.gif" a