condition mean min max ZT0-3 20.450000000000003 20.450000000000003 20.450000000000003 ZT4-7 6.9 6.9 6.9 ZT8-11 24.299999999999997 24.299999999999997 24.299999999999997 ZT12-15 19.25 19.25 19.25 ZT16-19 54.650000000000006 54.650000000000006 54.650000000000006 ZT20-23 27.95 27.95 27.95