condition mean min max ZT0-3 8.275673179 7.886461418 8.66488494 ZT4-7 5.49757783225 3.964004739 7.0311509255 ZT8-11 11.422655448 7.960185076 14.885125819999999 ZT12-15 10.4704837805 8.37423075 12.566736811 ZT16-19 7.40248747275 6.8394393595 7.965535586000001 ZT20-23 20.49745553 9.600420849999999 31.39449021