Sample Size Calculator

Determine the minimum sample size needed to achieve a desired margin of error at a given confidence level.

Sample Size (exact)

96.0400

Standard Error at This n1.5306

Sample Size (exact) vs Z-Value (e.g., 1.96 for 95%)

सूत्र देखें →

सूत्र

## How to Calculate Required Sample Size ### Formula **n = (z * sigma / E)^2** where E is the desired margin of error, z is the critical value for the confidence level, and sigma is the population standard deviation. Always round up to the next whole number since you cannot have a fractional observation.

हल किया गया उदाहरण

You want a 95% CI with margin of error 3 and estimated SD 15. How many observations are needed?

  1. 01n = (z * sigma / E)^2
  2. 02n = (1.96 * 15 / 3)^2
  3. 03n = (9.8)^2
  4. 04n = 96.04
  5. 05Round up: n = 97 observations needed