condition mean min max ZT0-3 8.0 8.0 8.0 ZT4-7 3.1 3.1 3.1 ZT8-11 12.850000000000001 12.850000000000001 12.850000000000001 ZT12-15 3.8499999999999996 3.8499999999999996 3.8499999999999996 ZT16-19 15.95 15.95 15.95 ZT20-23 1.8 1.8 1.8