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

z = (p-p₀) / √(p₀(1-p₀)/n)

where:

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

p₀ (hypothesized population proportion)

p (observed sample proportion)

n (sample size)

z-statistic: 0.55487

p-value (one-tailed): 0.28949

p-value (two-tailed): 0.57898

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