condition mean min max ZT0-3 7.658305 7.4375599999999995 7.87905 ZT4-7 4.734535 4.734535 4.734535 ZT8-11 6.569905 6.569905 6.569905 ZT12-15 0 0 0 ZT16-19 9.554965 9.554965 9.554965 ZT20-23 7.52618 7.52618 7.52618