condition mean min max ZT0-3 39.1 39.1 39.1 ZT4-7 8.8 8.8 8.8 ZT8-11 26.65 26.65 26.65 ZT12-15 19.35 19.35 19.35 ZT16-19 19.2 19.2 19.2 ZT20-23 4.85 4.85 4.85