Hello Sophia,
You could try something like this:
close all
load('PAM1.mat')
PAM1stats = grpstats(PAM1,["DHW","SHADE"],["min","max","mean","std"], "DataVars","FVFM"); %ONLY ONE VARIABLE AT ONCE
Data2Plot=PAM1stats{[1 4 7],6:7}; % Select the data you want to plot. In this case 0_0 , 4_0 and 6_0
p=plot([1,2,3],Data2Plot(:,1)','o','LineWidth',2,'MarkerFaceColor','k','MarkerEdgeColor','k');
hold on
e=errorbar([1,2,3],Data2Plot(:,1),-Data2Plot(:,2),Data2Plot(:,2),'LineWidth',1.5,'LineStyle','none','Color','k');
e(1).CapSize=18;
ax=gca;
ax.XLim=[0.5 3.5];
ax.XTick=[1 2 3];
ax.XTickLabel={'0-0';'4-0';'6-0'};
ax.FontName='Arial';
ax.FontSize=13;
ax.FontWeight='bold';
ax.TickDir='out';
ax.Box='off';
