Sample Size Calculator

Steps for Calculation

1. Input Values:
   • Population Size: Enter the total population size (e.g., 1000).
   • Confidence Level: Enter the confidence level as a percentage (e.g., 95 for 95%).
   • Margin of Error: Enter the margin of error as a percentage (e.g., 5 for 5%).
   • Population Proportion: Enter the estimated population proportion as a percentage (e.g., 50 for 50%).
2. Calculate Sample Size:
   • Click the Calculate Sample Size button to compute the required sample size.
3. View Result:
   • The required sample size will be displayed below the button.

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Detailed Description

• Sample Size Formula:
  The sample size is calculated using the formula for a finite population:n=Z2⋅p⋅(1−p)e21+(Z2⋅p⋅(1−p)e2⋅N)n=1+(e2⋅NZ2⋅p⋅(1−p)​)e2Z2⋅p⋅(1−p)​​Where:
  • nn = sample size,
  • ZZ = Z-score (based on the confidence level),
  • pp = population proportion (in decimal),
  • ee = margin of error (in decimal),
  • NN = population size.
• Z-Score:
  • The Z-score is determined by the confidence level. Common Z-scores are:
    • 80% confidence level: 1.28
    • 85% confidence level: 1.44
    • 90% confidence level: 1.645
    • 95% confidence level: 1.96
    • 99% confidence level: 2.576
• Example:
  • For a population size of 1000, a confidence level of 95%, a margin of error of 5%, and a population proportion of 50%:
    • Z-score = 1.96,
    • p=0.5p=0.5,
    • e=0.05e=0.05,
    • N=1000N=1000.
    • The calculated sample size is approximately 278.