condition mean min max ZT0-3 6.176515 6.176515 6.176515 ZT4-7 4.6902550000000005 4.6902550000000005 4.6902550000000005 ZT8-11 5.171615 5.171615 5.171615 ZT12-15 4.518685 4.518685 4.518685 ZT16-19 7.019195 7.019195 7.019195 ZT20-23 5.598775 5.598775 5.598775