condition mean min max ZT0-3 2.6366833333333335 1.917975 3.930985 ZT4-7 1.94535 1.94535 1.94535 ZT8-11 3.954495 3.954495 3.954495 ZT12-15 1.07152 0.0 2.14304 ZT16-19 3.81951 3.81951 3.81951 ZT20-23 4.230155 4.230155 4.230155