condition mean min max ZT0-3 1.7841016666666667 1.153985 2.715915 ZT4-7 7.84624 7.84624 7.84624 ZT8-11 15.70215 15.70215 15.70215 ZT12-15 5.377865 4.810615 5.9451149999999995 ZT16-19 5.339095 5.339095 5.339095 ZT20-23 4.291205 4.291205 4.291205