condition mean min max ZT0-3 17.881241 17.881241 17.881241 ZT4-7 21.997847 21.997847 21.997847 ZT8-11 17.223512999999997 17.223512999999997 17.223512999999997 ZT12-15 15.265808 15.265808 15.265808 ZT16-19 16.83467 16.83467 16.83467 ZT20-23 18.2187335 18.2187335 18.2187335