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One-Proportion z-TestStatLens

Choose a dataset:

Paste categorical data (one value per line, or CSV):

Open a CSV, TSV, or JSON file:

Number of successes: Sample size (n): Success label (optional):

Results update as you type — no need to press anything.

Variable:

Parameters

Count as success:

H₀: p =

H_a: p 0.5

Confidence level

Select a dataset or enter summary statistics — results appear automatically.

Just estimating? Confidence Interval for a Proportion →

One-Proportion z-Test

Test whether a population proportion p differs from a hypothesized value, using a z-statistic and the standard normal distribution.

Load data from the Datasets, Edit Data (one value per line), or Open File/URL tab, or use Enter Summary to type the number of successes and n.
Count as success: when the data has categories, pick which one counts as a success.
Null value: type the hypothesized proportion p₀ in the H₀ row (defaults to 0.5).
Alternative (H_a): click the toggle to cycle ≠, <, > for a two-sided or one-sided test.
Conditions checkpoint checks the success/failure counts (np₀ and n(1−p₀) ≥ 10).
Confidence level sets the matching interval (default 0.95).
Results — the z-statistic, p-value, confidence interval, and plot — appear automatically as you change inputs. There is no Compute button.

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