condition mean min max ZT0-3 35.85465 35.85465 35.85465 ZT4-7 25.1984 25.1984 25.1984 ZT8-11 16.793999999999997 16.793999999999997 16.793999999999997 ZT12-15 23.0518 23.0518 23.0518 ZT16-19 27.442300000000003 27.442300000000003 27.442300000000003 ZT20-23 33.45845 33.45845 33.45845