condition mean min max ZT0-3 3.2897 3.2897 3.2897 ZT4-7 2.862545 2.862545 2.862545 ZT8-11 3.20888 3.20888 3.20888 ZT12-15 3.24775 3.24775 3.24775 ZT16-19 4.340475 4.340475 4.340475 ZT20-23 3.25392 3.25392 3.25392