condition mean min max ZT0-3 2.4195218333333335 1.0479855 3.359395 ZT4-7 1.37882 1.37882 1.37882 ZT8-11 1.4611399999999999 1.4611399999999999 1.4611399999999999 ZT12-15 2.833995 2.5836699999999997 3.08432 ZT16-19 3.176265 3.176265 3.176265 ZT20-23 3.586615 3.586615 3.586615