condition mean min max ZT0-3 5.331795 5.331795 5.331795 ZT4-7 4.434215 4.434215 4.434215 ZT8-11 5.7526150000000005 5.7526150000000005 5.7526150000000005 ZT12-15 6.996029999999999 6.996029999999999 6.996029999999999 ZT16-19 10.91038 10.91038 10.91038 ZT20-23 6.55735 6.55735 6.55735