condition mean min max ZT0-3 8.386119193999999 8.05764392 8.714594468 ZT4-7 7.423661677 6.254352723 8.592970631 ZT8-11 8.07859825775 8.0277870715 8.129409444 ZT12-15 10.609801549 8.704961653 12.514641444999999 ZT16-19 11.527699665 10.82992351 12.22547582 ZT20-23 15.828085467500001 14.48836089 17.167810045000003