Sample Size Calculator
Calculate minimum sample sizes for statistical tests, proportion comparisons, and process capability studies.
Use case: Known σ, estimate population mean within an acceptable margin of error (e.g. dimension, weight measurement)
Population std dev (or historical estimate)
Maximum acceptable estimation error (±E)
62
Min. Sample Size (estimate population mean)
Formula: n = ⌈ (zα/2 × σ / E)² ⌉
zα/2 = normal quantile for confidence level、σ = std dev、E = margin of error
If σ is unknown, use a small pilot sample or historical process data to estimate.