condition mean min max ZT0-3 6.349233538749999 4.050837636 8.6476294415 ZT4-7 13.051612885 10.76668986 15.33653591 ZT8-11 15.742464435 15.109125235 16.375803635 ZT12-15 9.239136928 7.281435224999999 11.196838631 ZT16-19 4.0573508805 4.0079050815 4.1067966795 ZT20-23 4.12353626075 3.5314526735 4.715619847999999