condition mean min max ZT0-3 28.314083333333333 19.4204 36.124399999999994 ZT4-7 17.472900000000003 17.472900000000003 17.472900000000003 ZT8-11 19.81165 19.81165 19.81165 ZT12-15 30.090775 29.021050000000002 31.1605 ZT16-19 31.25475 31.25475 31.25475 ZT20-23 39.15515 39.15515 39.15515