condition mean min max ZT0-3 1.9987199999999998 1.5407199999999999 2.3949 ZT4-7 1.1650515 1.1650515 1.1650515 ZT8-11 1.619095 1.619095 1.619095 ZT12-15 2.4876975 2.09612 2.879275 ZT16-19 2.305875 2.305875 2.305875 ZT20-23 2.17489 2.17489 2.17489