condition mean min max ZT0-3 35.928325 31.64015 40.2165 ZT4-7 38.6428 38.6428 38.6428 ZT8-11 55.5517 55.5517 55.5517 ZT12-15 0 0 0 ZT16-19 69.95425 69.95425 69.95425 ZT20-23 59.6252 59.6252 59.6252