condition mean min max ZT0-3 55.444966 55.444966 55.444966 ZT4-7 43.6443805 43.6443805 43.6443805 ZT8-11 38.5205215 38.5205215 38.5205215 ZT12-15 32.664908 32.664908 32.664908 ZT16-19 30.9241405 30.9241405 30.9241405 ZT20-23 33.3606155 33.3606155 33.3606155