| i | x | fi | pi | npi | (fi-npi) |  |
|---|---|---|---|---|---|---|
| 1 | 0 | 38 | 0.069 | 29.183 | 8.817 | 2.664 |
| 2 | 1 | 86 | 0.185 | 77.821 | 8.179 | 0.860 |
| 3 | 2 | 90 | 0.247 | 103.762 | -13.762 | 1.825 |
| 4 | 3 | 82 | 0.220 | 92.233 | -10.233 | 1.135 |
| 5 | 4 | 55 | 0.146 | 61.489 | -6.489 | 0.685 |
| 6 | 5 | 41 | 0.078 | 32.794 | 8.206 | 2.053 |
| 7 | 6 | 16 | 0.035 | 14.575 | 1.425 | 0.139 |
| 8 | 7 | 9 | 0.013 | 5.552 | 3.448 | 2.141 |
| 9 | 8 above | 3 | 0.006 | 2.591 | 0.409 | 0.065 |
| Total | 420 | 1.000 | 420.000 | 0.000 | 11.567 |
i is each interval; x is the arrival number per minute