Proportion Estimation

Estimate a single population proportion or prevalence (P) with a specified precision (margin of error) and confidence.

Formula Used (Sample Size, n):

$$n = \frac{Z_{1-\alpha/2}^2 \cdot P (1-P)}{E^2}$$

Where E is the margin of error, P is the estimated proportion, and Z_1-α/2 is the Z-score for the desired confidence.

1. Estimated Proportion (P):

Expected prevalence or proportion (0.5 maxes sample size).

2. Margin of Error (E):

The maximum acceptable difference (e.g., 0.05 for ±5%).

3. Confidence Level (1-α):

Probability that the confidence interval contains the true proportion.

← Back to Calculators