condition mean min max ZT0-3 6.94282184775 6.500817059499999 7.3848266360000006 ZT4-7 3.17504460825 2.5579590415 3.7921301749999996 ZT8-11 1.849921026 1.7993250505 1.9005170015000001 ZT12-15 2.6831445560000002 2.4375257005 2.9287634115 ZT16-19 2.4089616235 2.1055312815000002 2.7123919655 ZT20-23 8.6727036425 5.1453856115 12.2000216735