condition mean min max ZT0-3 3.31796 3.31796 3.31796 ZT4-7 4.201915 4.201915 4.201915 ZT8-11 2.017765 2.017765 2.017765 ZT12-15 1.48942 1.48942 1.48942 ZT16-19 2.7189 2.7189 2.7189 ZT20-23 2.66707 2.66707 2.66707