condition mean min max ZT0-3 5.85 5.85 5.85 ZT4-7 2.4 2.4 2.4 ZT8-11 26.15 26.15 26.15 ZT12-15 6.5 6.5 6.5 ZT16-19 3.0999999999999996 3.0999999999999996 3.0999999999999996 ZT20-23 5.35 5.35 5.35