When assessing goodness of fit, remember that a statistically significant Z statistic means that the chosen distribution does not fit the data well. Unlike the previous test, however, we see a much better fit when splitting the file by gender.

  • Increasing the Poisson parameter from 1.72 to 1.98 clearly provides a better fit to the accident data for men.
  • Similarly, decreasing the Poisson parameter from 1.72 to 1.47 provides a better fit to the accident data for women.