condition mean min max ZT0-3 417.610468 417.610468 417.610468 ZT4-7 395.1069735 395.1069735 395.1069735 ZT8-11 357.146616 357.146616 357.146616 ZT12-15 337.2494075 337.2494075 337.2494075 ZT16-19 334.1725715 334.1725715 334.1725715 ZT20-23 348.4054105 348.4054105 348.4054105