condition mean min max ZT0-3 1.608775 1.608775 1.608775 ZT4-7 2.38757 2.38757 2.38757 ZT8-11 2.23427 2.23427 2.23427 ZT12-15 3.12817 3.12817 3.12817 ZT16-19 3.67872 3.67872 3.67872 ZT20-23 1.9073950000000002 1.9073950000000002 1.9073950000000002