condition mean min max ZT0-3 15.62216912 15.04237878 16.20195946 ZT4-7 16.811374035 15.645635004999999 17.977113065 ZT8-11 20.9340800375 19.214588425 22.65357165 ZT12-15 23.4077316375 23.277941204999998 23.53752207 ZT16-19 19.4852265125 18.228807070000002 20.741645955 ZT20-23 24.3908787025 23.22783045 25.553926955