condition mean min max ZT0-3 6.120535 5.21304 7.6163799999999995 ZT4-7 5.9035899999999994 5.9035899999999994 5.9035899999999994 ZT8-11 4.5082 4.5082 4.5082 ZT12-15 6.4140250000000005 5.974925 6.853125 ZT16-19 5.660945 5.660945 5.660945 ZT20-23 6.183809999999999 6.183809999999999 6.183809999999999