condition mean min max ZT0-3 13.895975 11.66095 16.131 ZT4-7 8.74999 8.74999 8.74999 ZT8-11 11.38415 11.38415 11.38415 ZT12-15 0 0 0 ZT16-19 9.424040000000002 9.424040000000002 9.424040000000002 ZT20-23 8.712724999999999 8.712724999999999 8.712724999999999