condition mean min max ZT0-3 2.069015 2.069015 2.069015 ZT4-7 3.01614 3.01614 3.01614 ZT8-11 1.843545 1.843545 1.843545 ZT12-15 1.434638 1.434638 1.434638 ZT16-19 3.451635 3.451635 3.451635 ZT20-23 3.38568 3.38568 3.38568