condition mean min max ZT0-3 28.3597 28.3597 28.3597 ZT4-7 26.0601 26.0601 26.0601 ZT8-11 13.606300000000001 13.606300000000001 13.606300000000001 ZT12-15 13.636700000000001 13.636700000000001 13.636700000000001 ZT16-19 20.753466666666668 20.753466666666668 20.753466666666668 ZT20-23 29.314999999999998 29.314999999999998 29.314999999999998