Ekuation

test type

Z-Test P-Value Calculator

Calculate the p-value for one-tailed or two-tailed z-tests based on the z-score.

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The probability threshold (alpha) for rejecting the null hypothesis. Common values are 0.05 or 0.01.

The hypothesized population mean you are testing against.

Use the Z-test only when the true population σ is known (e.g., from census data or known process specs). Otherwise use the t-test.

Test Formula
z=xˉμσ/nz = \frac{\bar{x} - \mu}{\sigma / \sqrt{n}}
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Try an Example

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Clinical Trial

One-sample t-test for a drug trial measuring blood pressure reduction.

Key values: Sample mean: 105 · Pop. mean: 100 · n = 30, SD = 15

A/B Test

Two-sample t-test comparing conversion rates between control and variant.

Key values: Group 1: 52, n=200 · Group 2: 48, n=200 · Two-tailed

Before-After Study

Paired t-test measuring weight loss in a fitness program.

Key values: Mean diff: 3.5 kg · SD diff: 2.1 · 25 pairs

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