condition mean min max ZT0-3 15.37935 15.37935 15.37935 ZT4-7 11.5687 11.5687 11.5687 ZT8-11 10.827 10.827 10.827 ZT12-15 12.73 12.73 12.73 ZT16-19 16.1418 16.1418 16.1418 ZT20-23 16.67285 16.67285 16.67285