condition mean min max ZT0-3 6.775195 6.775195 6.775195 ZT4-7 7.0044249999999995 7.0044249999999995 7.0044249999999995 ZT8-11 11.63795 11.63795 11.63795 ZT12-15 7.527939999999999 7.527939999999999 7.527939999999999 ZT16-19 8.41755 8.41755 8.41755 ZT20-23 7.19107 7.19107 7.19107