condition mean min max ZT0-3 2.078953333333333 1.712825 2.39801 ZT4-7 2.63865 2.63865 2.63865 ZT8-11 1.25971 1.25971 1.25971 ZT12-15 2.9158025 2.86795 2.963655 ZT16-19 2.23875 2.23875 2.23875 ZT20-23 2.2080900000000003 2.2080900000000003 2.2080900000000003