condition mean min max ZT0-3 1.7000000000000002 1.7000000000000002 1.7000000000000002 ZT4-7 4.6 4.6 4.6 ZT8-11 1.4500000000000002 1.4500000000000002 1.4500000000000002 ZT12-15 1.8 1.8 1.8 ZT16-19 2.8499999999999996 2.8499999999999996 2.8499999999999996 ZT20-23 5.85 5.85 5.85