condition mean min max ZT0-3 6.377238333333333 5.355174999999999 7.198125 ZT4-7 9.662455000000001 9.662455000000001 9.662455000000001 ZT8-11 7.847995 7.847995 7.847995 ZT12-15 8.6567525 7.6477 9.665805 ZT16-19 8.2684 8.2684 8.2684 ZT20-23 6.84004 6.84004 6.84004