1. Sample Size Calculation Table (Baseline Data)
This table estimates the required sample size based on baseline prevalence, expected change, confidence level, and margin of error (ME).
| Baseline Prevalence (%) | Expected Change (%) | Margin of Error (±%) | 95% Confidence Level (Z=1.96) | 99% Confidence Level (Z=2.58) |
|---|
| 5 | 2 | 5 | 1536 | 2577 |
| 10 | 3 | 5 | 921 | 1546 |
| 20 | 5 | 5 | 512 | 860 |
| 30 | 7 | 5 | 398 | 669 |
| 40 | 10 | 5 | 368 | 618 |
| 50 | 10 | 5 | 384 | 643 |
| 60 | 10 | 5 | 368 | 618 |
| 70 | 7 | 5 | 398 | 669 |
| 80 | 5 | 5 | 512 | 860 |
| 90 | 3 | 5 | 921 | 1546 |
2. Key Variables in Sample Size Calculation
| Variable | Definition | Typical Values |
|---|
| Baseline Prevalence (p1) | The proportion of the population affected before the intervention. | 5% – 90% |
| Expected Change (p2) | The expected increase or decrease in prevalence. | 2% – 10% |
| Margin of Error (E) | The acceptable error in the estimate. | 3% – 5% |
| Confidence Level (Z-score) | The level of certainty (typically 95% or 99%). | 1.96 (95%), 2.58 (99%) |
| Sample Size (n) | The minimum number of observations needed. | Depends on inputs |