condition mean min max ZT0-3 1.65 1.65 1.65 ZT4-7 2.7 2.7 2.7 ZT8-11 3.25 3.25 3.25 ZT12-15 5.9 5.9 5.9 ZT16-19 1.7999999999999998 1.7999999999999998 1.7999999999999998 ZT20-23 2.9 2.9 2.9