condition mean min max ZT0-3 15.255643 15.255643 15.255643 ZT4-7 19.3422775 19.3422775 19.3422775 ZT8-11 17.8112555 17.8112555 17.8112555 ZT12-15 16.633076000000003 16.633076000000003 16.633076000000003 ZT16-19 16.585537000000002 16.585537000000002 16.585537000000002 ZT20-23 18.755603 18.755603 18.755603