condition mean min max ZT0-3 15.663284 15.663284 15.663284 ZT4-7 16.353006 16.353006 16.353006 ZT8-11 17.8523245 17.8523245 17.8523245 ZT12-15 15.966349 15.966349 15.966349 ZT16-19 16.0228935 16.0228935 16.0228935 ZT20-23 16.14905 16.14905 16.14905