condition mean min max ZT0-3 6.6269100000000005 6.6269100000000005 6.6269100000000005 ZT4-7 4.31875 4.31875 4.31875 ZT8-11 5.078094999999999 5.078094999999999 5.078094999999999 ZT12-15 7.15864 7.15864 7.15864 ZT16-19 9.883455000000001 9.883455000000001 9.883455000000001 ZT20-23 9.020980000000002 9.020980000000002 9.020980000000002