condition mean min max ZT0-3 29.35 29.35 29.35 ZT4-7 8.0 8.0 8.0 ZT8-11 9.15 9.15 9.15 ZT12-15 6.7 6.7 6.7 ZT16-19 11.75 11.75 11.75 ZT20-23 7.55 7.55 7.55