condition mean min max ZT0-3 17.662 6.76095 25.2745 ZT4-7 15.06225 15.06225 15.06225 ZT8-11 17.4252 17.4252 17.4252 ZT12-15 15.2974925 8.163834999999999 22.431150000000002 ZT16-19 22.662300000000002 22.662300000000002 22.662300000000002 ZT20-23 26.40995 26.40995 26.40995