condition mean min max ZT0-3 15.416587 15.416587 15.416587 ZT4-7 14.0293895 14.0293895 14.0293895 ZT8-11 15.0888885 15.0888885 15.0888885 ZT12-15 16.5202235 16.5202235 16.5202235 ZT16-19 16.7366785 16.7366785 16.7366785 ZT20-23 13.7313245 13.7313245 13.7313245