| Testing Mean with known Variance | |
| sample size | 320 |
| population variance | 4.5 |
| sample mean | 4.2 |
| null hypothesis about mean | 4.5 |
| type I error | 0.05 |
| critical value (one-tailed) | 4.30494435454667 |
| confidence interval (two-tailed) (sample mean) | [ 3.96757686288579 , 4.43242313711421 ] |
| conclusion for one-tailed test | |
| Reject the null hypothesis. | |
| conclusion for two-tailed test | |
| Reject the null hypothesis | |