Use a Poisson distribution to represent data where the attribute of interest can appear an infinite number of times. Data include k counts. Listed below are the steps Minitab uses to compute ANOM results for data with a Poisson distribution.
where hα = inverse cumulative probability of α2 for the standard normal distribution, where α2 = 1 -α / (2 * k).
If the number of rows in your response column (k) equal 2, then α2 = 1 -α / 2