Sample Size Calculator

Select Calculation Mode

Use 50% if not sure

Leave blank if unlimited population size

Statistical Visualization

About Sample Size Calculation

In statistics, information is often inferred about a population by studying a finite number of individuals from that population. This calculator computes the minimum number of necessary samples to meet the desired statistical constraints using confidence intervals and margin of error.

Key Concepts:

  • Confidence Level: Probability that the true value falls within the confidence interval
  • Margin of Error: Maximum expected difference between sample and population values
  • Population Proportion: Estimated percentage of the population with the characteristic
  • Population Size: Total number of subjects in the study population

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Calculation Tips

  • Use 50% population proportion if unsure - gives maximum sample size
  • 95% confidence level is standard for most research
  • Leave population size blank for large/infinite populations
  • Smaller margin of error requires larger sample size

About Sample Size

Sample size determination is crucial in statistics to ensure results are statistically significant. The calculator uses the standard formula considering confidence level, margin of error, and population parameters to provide accurate sample size estimates for surveys and experiments.

Note: Calculations assume normal distribution and use z-scores for confidence intervals.