condition mean min max ZT0-3 41.400000000000006 41.400000000000006 41.400000000000006 ZT4-7 21.1 21.1 21.1 ZT8-11 1.95 1.95 1.95 ZT12-15 33.3 33.3 33.3 ZT16-19 33.75 33.75 33.75 ZT20-23 23.6 23.6 23.6