condition mean min max ZT0-3 8.572222222 8.572222222 8.572222222 ZT4-7 9.285 9.285 9.285 ZT8-11 12.34388889 12.34388889 12.34388889 ZT12-15 24.995555553333332 24.995555553333332 24.995555553333332 ZT16-19 27.57 27.57 27.57 ZT20-23 33.50777778 33.50777778 33.50777778