Publication date: 05/24/2021

One Sample Proportion Calculator Fields

Specify the following quantities and test settings:


The probability of a type I error, which is the probability of rejecting the null hypothesis when it is true. It is commonly referred to as the significance level of the test. The default alpha level is 0.05.


The true proportion, which could be known or hypothesized. The default value is 0.1.

Tip: For all other parameters fixed, the largest sample size occurs when the proportion is 0.5.


Select a method. Choices are Exact Agresti-Coull or Exact Clopper-Pearson. The Clopper-Pearson method tends to be more conservative (larger sample size) than the Agresti-Coull method.

One-Sided or Two-Sided

Select either a one-sided or a two-sided test.

Specify two of the following parameters to calculate the third value, or specify one value to obtain a plot of the relationship between the other two parameters.

Note: The plot uses the normal approximation method rather than an exact method.

Null Proportion

The proportion to test against (p0). The default value is 0.2.

Sample Size

The total number of observations (runs, experimental units, or samples) in the experiment.


The probability of rejecting the null hypothesis when it is false. With all other parameters fixed, power increases as sample size increases.

Calculator Buttons


Evaluates the missing value when two parameters are specified, or launches a plot comparing two missing parameters if only one parameter is specified.


Returns to the previous Sample Size and Power launch window.

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