condition mean min max ZT0-3 60.006393875 52.61650697 67.39628078 ZT4-7 35.1981775175 35.064012185 35.33234285 ZT8-11 29.350466320000002 29.31088236 29.39005028 ZT12-15 16.420211145000003 16.053776935000002 16.786645355 ZT16-19 20.45468102 19.90214459 21.00721745 ZT20-23 24.6528301275 24.574885719999997 24.730774535000002