condition mean min max ZT0-3 224.494506 224.494506 224.494506 ZT4-7 204.1161965 204.1161965 204.1161965 ZT8-11 232.22386799999998 232.22386799999998 232.22386799999998 ZT12-15 303.38969699999996 303.38969699999996 303.38969699999996 ZT16-19 296.606701 296.606701 296.606701 ZT20-23 410.8702625 410.8702625 410.8702625