condition mean min max ZT0-3 2.36142 2.36142 2.36142 ZT4-7 2.2465849999999996 2.2465849999999996 2.2465849999999996 ZT8-11 1.66993 1.66993 1.66993 ZT12-15 2.059265 2.059265 2.059265 ZT16-19 3.030035 3.030035 3.030035 ZT20-23 2.9958799999999997 2.9958799999999997 2.9958799999999997