condition mean min max ZT0-3 7.526485 6.0131250000000005 8.633205 ZT4-7 16.957 16.957 16.957 ZT8-11 21.1154 21.1154 21.1154 ZT12-15 44.36965 39.5218 49.2175 ZT16-19 17.08165 17.08165 17.08165 ZT20-23 9.448755 9.448755 9.448755