condition mean min max ZT0-3 6.65 6.65 6.65 ZT4-7 2.6 2.6 2.6 ZT8-11 15.95 15.95 15.95 ZT12-15 25.400000000000002 25.400000000000002 25.400000000000002 ZT16-19 8.45 8.45 8.45 ZT20-23 4.25 4.25 4.25