condition mean min max ZT0-3 6.424272500000001 4.35709 8.491455 ZT4-7 6.620535 6.620535 6.620535 ZT8-11 7.008970000000001 7.008970000000001 7.008970000000001 ZT12-15 0 0 0 ZT16-19 7.619225 7.619225 7.619225 ZT20-23 2.5496250000000003 2.5496250000000003 2.5496250000000003