condition mean min max ZT0-3 2.8047500000000003 2.8047500000000003 2.8047500000000003 ZT4-7 1.3743599999999998 1.3743599999999998 1.3743599999999998 ZT8-11 0.9651135 0.9651135 0.9651135 ZT12-15 0.909272 0.909272 0.909272 ZT16-19 3.549945 3.549945 3.549945 ZT20-23 3.8194299999999997 3.8194299999999997 3.8194299999999997