condition mean min max ZT0-3 7.895781666666666 4.274095 12.17339 ZT4-7 8.164655 8.164655 8.164655 ZT8-11 8.621110000000002 8.621110000000002 8.621110000000002 ZT12-15 8.3401925 8.26175 8.418635 ZT16-19 14.10245 14.10245 14.10245 ZT20-23 10.54625 10.54625 10.54625