$Sample Size$

Sample Size

Sample size from confidence level, margin of error and population size, plus the margin of error for a known sample.

What to find:

How many people to survey

What the margin of error will be

If the expected proportion is unknown, keep 50%: it gives the largest and safest sample.

Sample size tells you how many people to survey so that the result stays within a given margin of the true value.

n₀ = z² · p(1 − p) / E²

For a small population, apply the correction n = n₀ / (1 + (n₀ − 1) / N). The formula assumes random sampling.

Comments

No comments yet.

Linked Calculators

$Confidence Interval Calculator: Mean and Proportion$

$Correlation and Linear Regression Calculator: Least Squares$

$Permutation Calculator: Inverse, Inversions, Cycles and Order$

$Binomial Theorem and Pascal’s Triangle Calculator$

$Combinatorial Equation Solver: Combinations and Permutations$

$Permutations and Combinations Calculator (nPr, nCr)$