condition mean min max ZT0-3 0.9577739999999999 0.8955675 1.006716 ZT4-7 1.872555 1.872555 1.872555 ZT8-11 3.1852650000000002 3.1852650000000002 3.1852650000000002 ZT12-15 2.0893075 1.773055 2.40556 ZT16-19 1.6789749999999999 1.6789749999999999 1.6789749999999999 ZT20-23 1.51075 1.51075 1.51075