condition mean min max ZT0-3 3.470283333333333 3.06898 4.223095 ZT4-7 6.116715 6.116715 6.116715 ZT8-11 5.719995 5.719995 5.719995 ZT12-15 9.353394999999999 8.18059 10.5262 ZT16-19 7.63866 7.63866 7.63866 ZT20-23 6.0240849999999995 6.0240849999999995 6.0240849999999995