condition mean min max ZT0-3 1.7 1.7 1.7 ZT4-7 2.6 2.6 2.6 ZT8-11 1.8499999999999999 1.8499999999999999 1.8499999999999999 ZT12-15 2.8 2.8 2.8 ZT16-19 2.9 2.9 2.9 ZT20-23 4.25 4.25 4.25