Joint Bayesian Treatment of Poisson and Gaussian Experiments in a   Chi-squared Statistic
  Bayesian Poisson probability distributions for the average n can be analytically converted into equivalent chi-squared distributions. These can then be combined with other Gaussian or Bayesian Poisson distributions to make a total chi-squared distribution. This allows the usual treatment of chi-squared contours but now with both Poisson and Gaussian statistics experiments. This is illustrated with the case of neutrino oscillations. 
Dennis Silverman (U. C. Irvine)