condition mean min max ZT0-3 4.985545 4.600585000000001 5.370505 ZT4-7 3.9055150000000003 3.9055150000000003 3.9055150000000003 ZT8-11 3.5760199999999998 3.5760199999999998 3.5760199999999998 ZT12-15 0 0 0 ZT16-19 6.203825 6.203825 6.203825 ZT20-23 6.55276 6.55276 6.55276