condition mean min max ZT0-3 61.39855 55.1687 67.6284 ZT4-7 34.68105 34.68105 34.68105 ZT8-11 25.264899999999997 25.264899999999997 25.264899999999997 ZT12-15 0 0 0 ZT16-19 41.8404 41.8404 41.8404 ZT20-23 58.0773 58.0773 58.0773