Hi! I believe you could use the errorbar function. Here's an example:
% Create groups and data
X = categorical({'Small','Medium','Large','Extra Large'});
X = reordercats(X,{'Small','Medium','Large','Extra Large'});
Y = [10 21 33 52];
% Make a bar plot
bar(X,Y)
% Plot on top of bar plot
hold on
% errorbar(x,y,ci,marker) where ci is the height of the line. This can be
% computed from your confidence intervals.
errorbar([1 2 3 4],[10 21 33 52],[4 6 7 8],'o')
If this works for you, please formally accept this answer.
