condition mean min max ZT0-3 31.15 31.15 31.15 ZT4-7 14.8 14.8 14.8 ZT8-11 17.1 17.1 17.1 ZT12-15 33.3 33.3 33.3 ZT16-19 31.200000000000003 31.200000000000003 31.200000000000003 ZT20-23 32.95 32.95 32.95