Normal Probability Sampling Distributions Calculator
Calculate normal probability sampling distributions — sample size for surveys and polls.
—
Sample Size
—
Minimum Sample
Recent Calculations
What Is Normal Probability Sampling Distributions?
Normal Probability Sampling Distributions estimates the sample size needed for a survey given confidence level, margin of error, and proportion.
Formula
n = z² × p(1−p) / E²Frequently Asked Questions
What confidence level should I use?
95% is standard for most surveys. 99% gives wider intervals and requires larger samples.