The 95% confidence interval for mean defective is calculated as follows:


| Term | Description |
|---|---|
| v1 | 2 * Dtot |
| v2 | 2 * (Dtot + 1) |
| Dtot | Sum of all the defectives |
| N | Number of samples |
The 95% confidence interval for mean defects per unit is calculated as follows:


| Term | Description |
|---|---|
| v1 | 2 * Dtot |
| v2 | 2 * (Dtot + 1) |
| Dtot | Sum of all the defectives |
| Ntot | Sum of all the sample sizes |