condition mean min max ZT0-3 2.57625 2.22701 2.92549 ZT4-7 3.25881 3.25881 3.25881 ZT8-11 2.8682749999999997 2.8682749999999997 2.8682749999999997 ZT12-15 0 0 0 ZT16-19 2.7098250000000004 2.7098250000000004 2.7098250000000004 ZT20-23 3.2773849999999998 3.2773849999999998 3.2773849999999998