condition mean min max ZT0-3 3.2 3.2 3.2 ZT4-7 12.9 12.9 12.9 ZT8-11 8.65 8.65 8.65 ZT12-15 31.849999999999998 31.849999999999998 31.849999999999998 ZT16-19 17.95 17.95 17.95 ZT20-23 4.6000000000000005 4.6000000000000005 4.6000000000000005