Sample Size Calculator
Estimate sample size needed for a target margin of error.
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What This Calculator Does
Estimate sample size needed for a target margin of error.
It combines Z Value, Estimated SD, Margin of Error to estimate Required Sample Size.
Formula & Method
Core equations: Proportion sample size: n=\frac{z^2p(1-p)}{E^2} (with finite-pop correction if used).
Notation used in the formulas: R = Required Sample Size; x_{1} = Z Value; x_{2} = Estimated SD; x_{3} = Margin of Error.
Method summary: inputs are normalized to consistent units, core equations are evaluated, then secondary values are derived and rounded for display.
Use this calculator for quick scenario analysis. Start with baseline values, change one driver at a time, and compare how sensitive the results are to each input shown above.
Inputs Used
- Z Value: Used directly in the calculation.
- Estimated SD: Used directly in the calculation.
- Margin of Error: Used directly in the calculation.
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