condition mean min max ZT0-3 0.0485728 0.0485728 0.0485728 ZT4-7 0.03203585 0.03203585 0.03203585 ZT8-11 0.06983265 0.06983265 0.06983265 ZT12-15 0.037161849999999996 0.037161849999999996 0.037161849999999996 ZT16-19 0.15539540000000002 0.15539540000000002 0.15539540000000002 ZT20-23 0.069843 0.069843 0.069843