condition mean min max ZT0-3 3.5940833333333333 2.300325 4.8953299999999995 ZT4-7 3.33389 3.33389 3.33389 ZT8-11 4.742855 4.742855 4.742855 ZT12-15 5.542035 4.359125 6.724945 ZT16-19 5.9351400000000005 5.9351400000000005 5.9351400000000005 ZT20-23 6.817435 6.817435 6.817435