condition mean min max ZT0-3 4.157531666666666 2.73895 6.990355 ZT4-7 2.721705 2.721705 2.721705 ZT8-11 1.35603 1.35603 1.35603 ZT12-15 1.9225869999999998 1.018049 2.8271249999999997 ZT16-19 1.1076895 1.1076895 1.1076895 ZT20-23 1.86478 1.86478 1.86478