# Enter your data for Power and Sample Size for 1-Sample Poisson Rate

Stat > Power and Sample Size > 1-Sample Poisson Rate

Complete the following steps to specify the data for the power and sample size calculation.

1. Specify values for two of the following power function variables. Leave the variable that you want to calculate blank.
• Sample sizes: Enter a sample size of interest. To assess the effect of different sample sizes, enter multiple values. Larger sample sizes give the test more power to detect a difference.
###### Tip

If you enter multiple values into a field, separate the values with a space. You can also use shorthand notation to indicate multiple values. For example, you can enter 10:40/5 to indicate sample sizes from 10 to 40 in increments of 5.

• Comparison rates: Enter one or more rates that are meaningfully different from the Hypothesized rate. Usually, the difference between the comparison rate and hypothesized rate is the smallest difference that has practical consequences for your application.

For example, an analyst enters 43 and 53 to determine whether the number of transactions per hour differs from the hypothesized rate of 48 by at least 5.

• Power values: Enter one or more values to specify the probability that the test detects a difference between each comparison rate and the hypothesized rate when a difference actually exists. Common values are 0.8 and 0.9. For example, an analyst enters 0.9 to have a 90% chance that the test will detect whether the number of transactions per hour is different than the target (hypothesized rate) when a difference actually exists.
2. Enter a value in Hypothesized rate. The Hypothesized rate defines your null hypothesis (H0: λ = λ0). Think of this value as a target value or a reference value. For example, an analyst enters 48 as the hypothesized rate to determine whether the number of transactions per hour is different from 48 (H0: λ = 48).
By using this site you agree to the use of cookies for analytics and personalized content.  Read our policy