Overview for 2-Sample Poisson Rate

Use 2-Sample Poisson Rate to do the following when your data are counts per unit.
  • Determine whether the population rates of occurrence for two groups differ.
  • Calculate a range of values that is likely to include the difference between the population rates.

For example, a traffic safety consultant wants to compare the number of cars per hour that travel on two different streets. If the rates from the two streets are different, the consultant uses the confidence interval to determine whether the difference is practically significant.

Where to find this analysis

To perform a 2-sample Poisson rate test, choose Stat > Basic Statistics > 2-Sample Poisson Rate.

When to use an alternate analysis

If your data classify each observation into one of two categories, such as pass/fail, use 2 Proportions. For more information on data types, go to Data types you can analyze with a hypothesis test.