condition mean min max ZT0-3 2.769205 2.58899 2.94942 ZT4-7 3.49798 3.49798 3.49798 ZT8-11 2.79712 2.79712 2.79712 ZT12-15 0 0 0 ZT16-19 3.735325 3.735325 3.735325 ZT20-23 3.091325 3.091325 3.091325