A **one proportion z-test** is used to compare an observed proportion to a theoretical one. The test statistic is calculated as:

where:

- p = observed sample proportion
- p
_{0}= hypothesized population proportion - n = sample size

To perform a one proportion z-test, simply fill in the information below and then click the “Calculate” button.

z-statistic: 0.55487

p-value (one-tailed): 0.28949

p-value (two-tailed): 0.57898

95% C.I. = [0.2914, 0.6486]