condition mean min max ZT0-3 7.3589575 5.50564 9.212275 ZT4-7 7.09555 7.09555 7.09555 ZT8-11 15.554849999999998 15.554849999999998 15.554849999999998 ZT12-15 0 0 0 ZT16-19 14.24895 14.24895 14.24895 ZT20-23 8.36331 8.36331 8.36331