condition mean min max ZT0-3 7.206368333333334 5.718755 8.248245 ZT4-7 3.2077400000000003 3.2077400000000003 3.2077400000000003 ZT8-11 4.2688950000000006 4.2688950000000006 4.2688950000000006 ZT12-15 3.8964774999999996 3.3725249999999996 4.42043 ZT16-19 3.3354799999999996 3.3354799999999996 3.3354799999999996 ZT20-23 7.1007 7.1007 7.1007