condition mean min max ZT0-3 117.641472 117.641472 117.641472 ZT4-7 84.3096765 84.3096765 84.3096765 ZT8-11 136.04129999999998 136.04129999999998 136.04129999999998 ZT12-15 108.1605785 108.1605785 108.1605785 ZT16-19 224.1888925 224.1888925 224.1888925 ZT20-23 172.954471 172.954471 172.954471