condition mean min max ZT0-3 4.591366666666667 2.2055 6.01919 ZT4-7 2.228515 2.228515 2.228515 ZT8-11 2.561365 2.561365 2.561365 ZT12-15 3.64346 2.869885 4.417035 ZT16-19 6.638645 6.638645 6.638645 ZT20-23 7.8440449999999995 7.8440449999999995 7.8440449999999995