One Proportion Z-Test Calculator

Test if a sample proportion differs from a hypothesized population proportion

About One Proportion Z-Test

Formula: z = (p̂ - p₀) / √(p₀(1-p₀)/n)

Assumptions:

  • Random sample
  • np₀ ≥ 10 and n(1-p₀) ≥ 10
  • Independence of observations

Wilson CI is recommended over Wald CI for better coverage.

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Editorial Note

MyCalcBuddy Editorial Team

This page is maintained as an educational calculator reference.

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Formula Source: Standard Mathematical References

by Various

🔄Last reviewed: May 2026
✓Formula checks are based on standard references and internal QA review.