condition mean min max ZT0-3 31.099999999999998 31.099999999999998 31.099999999999998 ZT4-7 15.6 15.6 15.6 ZT8-11 71.0 71.0 71.0 ZT12-15 74.69999999999999 74.69999999999999 74.69999999999999 ZT16-19 58.3 58.3 58.3 ZT20-23 34.95 34.95 34.95