Estimated power from various methods (no replicates). Estimated size and power from each method for detecting the difference of two Poisson means. There are no replicates for each condition. The Poisson means for the first condition are 5, 10, 15, or 30. The second Poisson means are the same as (for size) or larger than (for power) the first ones. The nominal size (significance level) is 10-3 and 10,000 runs are used for each setting.