condition mean min max ZT0-3 8.7 8.7 8.7 ZT4-7 20.4 20.4 20.4 ZT8-11 22.849999999999998 22.849999999999998 22.849999999999998 ZT12-15 3.75 3.75 3.75 ZT16-19 1.9500000000000002 1.9500000000000002 1.9500000000000002 ZT20-23 16.3 16.3 16.3