condition mean min max ZT0-3 9.650615 9.650615 9.650615 ZT4-7 9.066970000000001 9.066970000000001 9.066970000000001 ZT8-11 9.576843 9.576843 9.576843 ZT12-15 9.550469499999998 9.550469499999998 9.550469499999998 ZT16-19 8.846294499999999 8.846294499999999 8.846294499999999 ZT20-23 8.918918 8.918918 8.918918