condition mean min max ZT0-3 4.35 4.35 4.35 ZT4-7 9.0 9.0 9.0 ZT8-11 20.85 20.85 20.85 ZT12-15 7.449999999999999 7.449999999999999 7.449999999999999 ZT16-19 23.5 23.5 23.5 ZT20-23 44.25 44.25 44.25