condition mean min max ZT0-3 3.8004583333333337 3.443855 4.440065000000001 ZT4-7 3.8775049999999998 3.8775049999999998 3.8775049999999998 ZT8-11 4.26847 4.26847 4.26847 ZT12-15 5.35439 4.199715 6.509065 ZT16-19 6.2628699999999995 6.2628699999999995 6.2628699999999995 ZT20-23 3.92405 3.92405 3.92405