condition mean min max ZT0-3 2.074645 1.56055 2.608425 ZT4-7 1.4924149999999998 1.4924149999999998 1.4924149999999998 ZT8-11 3.07972 3.07972 3.07972 ZT12-15 4.8546975 3.48428 6.225115000000001 ZT16-19 3.85175 3.85175 3.85175 ZT20-23 4.09365 4.09365 4.09365