condition mean min max ZT0-3 8.7 8.7 8.7 ZT4-7 11.7 11.7 11.7 ZT8-11 53.5 53.5 53.5 ZT12-15 40.65 40.65 40.65 ZT16-19 27.35 27.35 27.35 ZT20-23 15.65 15.65 15.65