condition mean min max ZT0-3 9.9833939 9.43973696 10.52705084 ZT4-7 7.3515344232499995 6.7397760925 7.963292753999999 ZT8-11 5.612259164 4.6101125795 6.6144057485 ZT12-15 1.195151648 0.326949227 2.063354069 ZT16-19 0.20680193225 0.19603914249999999 0.217564722 ZT20-23 0.06797384549999999 0.0208001475 0.11514754349999999