condition mean min max ZT0-3 6.342865 6.342865 6.342865 ZT4-7 4.285825 4.285825 4.285825 ZT8-11 9.2362 9.2362 9.2362 ZT12-15 11.34165 11.34165 11.34165 ZT16-19 13.1441 13.1441 13.1441 ZT20-23 7.052375 7.052375 7.052375