condition mean min max ZT0-3 20.849999999999998 20.849999999999998 20.849999999999998 ZT4-7 1.0 1.0 1.0 ZT8-11 8.25 8.25 8.25 ZT12-15 3.05 3.05 3.05 ZT16-19 4.0 4.0 4.0 ZT20-23 12.45 12.45 12.45