condition mean min max ZT0-3 3.4491825 3.03237 3.865995 ZT4-7 3.6331700000000002 3.6331700000000002 3.6331700000000002 ZT8-11 6.37021 6.37021 6.37021 ZT12-15 0 0 0 ZT16-19 4.76501 4.76501 4.76501 ZT20-23 6.885535 6.885535 6.885535