1. What is the Sample Size Formula?

The finite population sample size formula calculates the required sample size (n) given a population size (N) and desired margin of error (e). It's used when sampling from a finite population without replacement.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( n \) — Required sample size (dimensionless)
• \( N \) — Total population size (dimensionless)
• \( e \) — Margin of error (dimensionless, typically 0.05 for 5%)

Explanation: The formula adjusts the sample size based on the population size and desired precision (margin of error).

3. Importance of Sample Size Calculation

Details: Proper sample size ensures study results are statistically significant while minimizing resource use. Too small samples may not detect effects, while too large wastes resources.

4. Using the Calculator

Tips: Enter population size as a whole number. Margin of error should be between 0 and 1 (e.g., 0.05 for 5% margin).

5. Frequently Asked Questions (FAQ)

Q1: What's a typical margin of error?
A: 0.05 (5%) is common for many studies, though stricter studies may use 0.01 (1%).

Q2: When should I use infinite vs finite population formulas?
A: Use finite formulas when sampling ≥5% of the population; otherwise infinite formulas may suffice.

Q3: Does this account for confidence level?
A: This simplified version assumes 95% confidence. More complex formulas include explicit confidence level terms.

Q4: How does population size affect sample size?
A: For small populations, sample size increases nearly proportionally. For large populations (>10,000), sample size changes minimally.

Q5: What if I need to account for response rate?
A: Divide the calculated sample size by your expected response rate (e.g., divide by 0.7 for 70% response rate).