condition mean min max ZT0-3 4.1375 4.1375 4.1375 ZT4-7 2.726305 2.726305 2.726305 ZT8-11 3.1044549999999997 3.1044549999999997 3.1044549999999997 ZT12-15 3.626825 3.626825 3.626825 ZT16-19 5.078950000000001 5.078950000000001 5.078950000000001 ZT20-23 4.16084 4.16084 4.16084