condition mean min max ZT0-3 1.35 1.35 1.35 ZT4-7 1.9 1.9 1.9 ZT8-11 15.600000000000001 15.600000000000001 15.600000000000001 ZT12-15 2.8499999999999996 2.8499999999999996 2.8499999999999996 ZT16-19 18.1 18.1 18.1 ZT20-23 3.9000000000000004 3.9000000000000004 3.9000000000000004