Try this —
r1=[19.38 65.3 15.32;16.66 62.13 21.21;18.21 58.31 23.49;19.11 59.95 20.94;16.53 67.27 16.19;19.41 63.87 16.72];
Std= [1.2141 3.0580 3.0398];
Mean=[18.2167 62.8050 18.9783];
Bar=bar(Mean,0.4, 'FaceColor', 'flat');
Bar.CData(1,:)=[0.8500 0.3250 0.0980];
Bar.CData(2,:)= [1 0 0];
Bar.CData(3,:)= [0 1 0];
set(gca,'FontSize',12,'XTick',[1 2 3 ],'XTickLabel',{'Empty space','Higher Diameter','Lower Diameter' });
xlabel('Percentage of spcace occupied ')
ylabel('Mean')
errbar=[Std];
yd=[Mean];
hold on
eb = errorbar(Bar.XEndPoints, Bar.YEndPoints, errbar, '.k', 'LineWidth',1, 'MarkerSize',0.1, 'DisplayName','Error Bars');
hb1 = bar(NaN,NaN, 'FaceColor',[0.8500 0.3250 0.0980], 'DisplayName','One');
hb2 = bar(NaN,NaN,'FaceColor',[1 0 0], 'DisplayName','Two');
hb3 = bar(NaN,NaN,'FaceColor',[0 1 0], 'DisplayName','Three');
hold off
legend([hb1,hb2,hb3,eb], 'Location','best')
.
