Sample Size Calculation for Two Sample Proportion
Expert Guide to Sample Size Calculation for Two Sample Proportion
Introduction & Importance
Sample size calculation for two-sample proportion is crucial in statistical analysis to ensure the validity and reliability of your results…
How to Use This Calculator
- Enter the significance level (α), power (1 – β), and proportions (p1, p2) for both groups.
- Click ‘Calculate’.
- View the results and chart below.
Formula & Methodology
The formula used in this calculator is based on the following equation…
Real-World Examples
Example 1: Drug Efficacy Study
Suppose we want to compare the efficacy of a new drug (p1) to a placebo (p2) in a clinical trial…
Example 2: Customer Satisfaction Survey
We want to compare the satisfaction rates of customers who received different types of support (p1 vs. p2).
Example 3: Political Poll
We want to estimate the proportion of voters who support (p1) or oppose (p2) a particular policy.
Data & Statistics
| α | Power | p1 | p2 | n (per group) |
|---|---|---|---|---|
| 0.05 | 0.8 | 0.6 | 0.4 | 64 |
| α | Power | p1 | p2 | n (per group) |
|---|---|---|---|---|
| 0.05 | 0.8 | 0.6 | 0.4 | 64 |
| 0.05 | 0.9 | 0.6 | 0.4 | 106 |
Expert Tips
- Always round up the calculated sample size to ensure you have enough participants.
- Consider using a software or statistical package to perform the calculations.
- Regularly review and update your sample size calculations as new data becomes available.
Interactive FAQ
What is the significance level (α)?
The significance level (α) is the probability of rejecting the null hypothesis when it is true. Common values are 0.05, 0.01, and 0.001.
What is power (1 – β)?
Power (1 – β) is the probability of detecting an effect when there is one. It’s often set to 0.8 or 0.9.
For more information, see the CDC’s Sample Size Calculator and the Duke University’s guide on two-sample proportion.