condition mean min max ZT0-3 19.900000000000002 19.900000000000002 19.900000000000002 ZT4-7 3.9 3.9 3.9 ZT8-11 8.25 8.25 8.25 ZT12-15 32.7 32.7 32.7 ZT16-19 21.45 21.45 21.45 ZT20-23 38.1 38.1 38.1