Stratified Sample Calculator

Calculate sample sizes for stratified random sampling

Total Sample Size (n):

Allocation Method:

Name:

Population (N):

Std Dev (optional):

Name:

Population (N):

Std Dev (optional):

Stratified sampling divides the population into homogeneous subgroups (strata) and samples from each stratum.

Allocation Methods:

Proportional: n_h = n × (N_h / N) - Sample sizes proportional to stratum sizes
Optimal (Neyman): n_h = n × (N_h × σ_h) / Σ(N_h × σ_h) - Accounts for stratum variability
Equal: Same sample size from each stratum

Stratified sampling often provides more precise estimates than simple random sampling, especially when strata are internally homogeneous.