This is not a homework problem so I'm asking it here. I just ran an MCMC and found the best fit parameters for a model of massive gravity. I now need to find the said 68% Confidence Interval interval for those parameters. I have never done anything like this before so I'm clueless where to begin or even look for reference. I have the parameter errors from the MCMC and the correlation matrix if any of that helps. Any help will be appreciated thank you.