condition mean min max ZT0-3 2.25 2.25 2.25 ZT4-7 0.9 0.9 0.9 ZT8-11 3.25 3.25 3.25 ZT12-15 2.75 2.75 2.75 ZT16-19 3.0999999999999996 3.0999999999999996 3.0999999999999996 ZT20-23 1.4 1.4 1.4