| Age | Mean | S.D. | Sample Size | Age Range | Confidence Interval of Difference |
|---|---|---|---|---|---|
| Private (Period I) | 42.9 | 10.0 | 428 | (17-79) | (-1.98, 4.08) |
| Non-private (Period I) | 41.9 | 11.8 | 65 | (15-68) | |
| Private (Period II) | 42.5 | 10.6 | 177 | (17-72) | (-4.51, 5.35) |
| Non-private (Period II) | 42.1 | 13.3 | 31 | (18-63) | |
| Private (Period III) | 44.3 | 11.4 | 132 | (20-78) | (-1.55, 3.07) |
| Non-private (Period III) | 43.5 | 12.1 | 351 | (19-84) |