condition mean min max ZT0-3 15.567025000000001 14.36875 16.7653 ZT4-7 6.51947 6.51947 6.51947 ZT8-11 5.937135 5.937135 5.937135 ZT12-15 0 0 0 ZT16-19 8.29618 8.29618 8.29618 ZT20-23 9.560490000000001 9.560490000000001 9.560490000000001