condition mean min max ZT0-3 39.650000000000006 39.650000000000006 39.650000000000006 ZT4-7 33.7 33.7 33.7 ZT8-11 31.75 31.75 31.75 ZT12-15 5.9 5.9 5.9 ZT16-19 19.5 19.5 19.5 ZT20-23 60.0 60.0 60.0