Calculate confidence intervals for a population mean (known or unknown σ) and population proportion at various confidence levels.
Use z-distribution when population standard deviation σ is known.
| Property | Value |
|---|---|
| Sample mean (x̄) | 50 |
| Critical value (z*) | 1.96 |
| Standard Error (σ/√n) | 1.8257 |
| Margin of Error | ±3.5785 |
| Lower bound | 46.4215 |
| Upper bound | 53.5785 |
| Confidence Level | z* | α |
|---|---|---|
| 80% | 1.2816 | 0.200 |
| 85% | 1.4395 | 0.150 |
| 90% | 1.6449 | 0.100 |
| 95% | 1.96 | 0.050 |
| 99% | 2.5758 | 0.010 |
| 99.5% | 2.807 | 0.005 |
| 99.9% | 3.2905 | 0.001 |