| One-sample test | ||||||
|
| Test value = 0 | |||||
| t | df | Sig. (2-tailed) | Mean difference | 95% confidence interval of the difference | ||
| Lower | Upper | |||||
| PPF in PWYW | 45.407 | 321 | 0.000 | 4.5497 | 4.353 | 4.747 |
| PPF in OPS | 40.607 | 321 | 0.000 | 3.6056 | 3.431 | 3.780 |