  The 'standard' confidence interval for a Poisson parameter is only one of a
number of estimation intervals based on the chi-square distribution that may be
used in the estimation of the mean or mean rate for a Poisson model. Other
chi-square intervals are available for experimenters using Bayesian or
structural inference methods. Exploring these intervals also leads to other
alternate approximate chi-square intervals. Although coverage probability may
not always be of interest for Bayesian or structural intervals, coverage
probabilities are useful for validating 'objective' priors. Coverage
probabilities are explored for all of the intervals considered.
