condition mean min max ZT0-3 6.526178333333333 6.0558499999999995 7.03339 ZT4-7 3.8985899999999996 3.8985899999999996 3.8985899999999996 ZT8-11 5.01613 5.01613 5.01613 ZT12-15 6.0773675 5.941245 6.21349 ZT16-19 4.5828299999999995 4.5828299999999995 4.5828299999999995 ZT20-23 7.682085 7.682085 7.682085