condition mean min max ZT0-3 5.508263333333333 5.508263333333333 5.508263333333333 ZT4-7 7.0814 7.0814 7.0814 ZT8-11 5.754555 5.754555 5.754555 ZT12-15 3.8023100000000003 3.8023100000000003 3.8023100000000003 ZT16-19 4.223050000000001 4.223050000000001 4.223050000000001 ZT20-23 3.92227 3.92227 3.92227