condition mean min max ZT0-3 8.950000000000001 8.950000000000001 8.950000000000001 ZT4-7 32.2 32.2 32.2 ZT8-11 35.849999999999994 35.849999999999994 35.849999999999994 ZT12-15 27.5 27.5 27.5 ZT16-19 9.5 9.5 9.5 ZT20-23 33.75 33.75 33.75