Plotting confidence interval with bar plot

Hi all,

I have the following graph, and I want to plot the mean and standard deviation (in grey) such that the these lines fit exactly to my x-axis bars. I would really like the grey shaded region to be a straight horizontal line in the region behind hte bars themselves, and only "slope" in the spaces between. Is there a way that I can do this?

[Gaurav Garg]

Hey Amy!!

it's very unclear by 'these lines fit exactly to my x-axis bars' because the plot of mean doesn't need to be a line and would plot the means on each point.

Could you elaborate a little more on your question, and also give an example (if possible) for better understanding?

[Amy Hassett]

Hi Gaurav,

Thank you for your message! I shall try to explain more and be a bit clearer.

In this graph, the black line, and the grey shaded area represet a group that I would like to compare my other groups (represented by the bars and individual points) to. So, I would like the shaded grey region to be horizontal in the space behind the bars, because the three bars have the same "x" value.

Is that any clearer?

[Gaurav Garg]

How are you plotting the black line and grey shaded area?

[Amy Hassett]

Using this code:

%%Plot figure
h = figure;
x = 1:numel(Behaviours); %% x axis values
yValues = norm_WT_std2_SH_allInfo(1, :); %% y values
plot(x, yValues, 'k-'); %plot black line
hold on;
plot(x, norm_WT_std2_SH_allInfo(2, :), 'LineWidth', 0.5, 'Color', 'white'); % upper boarder of shaded area
hold on;
plot(x, norm_WT_std2_SH_allInfo(3, :), 'LineWidth', 0.5 , 'Color', 'white'); % lower boarder of shaded area
x2 = [x, fliplr(x)]; %% code to fill in this area (from another matlab answers question
inBetween = [norm_WT_std2_SH_allInfo(2, :), fliplr(norm_WT_std2_SH_allInfo(3, :))];
f= fill(x2, inBetween, 'k');
set(f,'facealpha',.1)
set(f,'edgecolor','white');
set(gca,'TickDir','out');
hold on;

Answer 1

[Amy Hassett]

Hi All,

I actually found out how do this, to produce the following graph

and here is the code, should it be of any use to anyone

%%code for getting variables etc....

%%Bars 
YValues = vertcat(barSet1,  barSet2, barSet3 );
b = bar(x, YValues, 'FaceAlpha', 0.5, 'EdgeColor', 'none');
%%axes
drawnow;
hold on;
set(gca,'XTick',1:numel(Behaviours),'XTickLabel',Behaviours);
set(gca, 'FontName', 'Arial')
xtickangle(45);
hold on; 

%%Scatter plots:
for i = 1:size(scatterPoints1,1)
    s(1) = scatter(x+b(1).XOffset, scatterPoints1(i,:), 50, 'MarkerFaceColor', '#ff4343', 'MarkerEdgeColor', '#ff4343')
    hold on
end
X_pos_firstBar =x+b(1).XOffset %% this gives the x-locations of each bar

for i = 1:size(scatterPoints2,1)
    s(2) = scatter(x+b(2).XOffset, scatterPoints2(i,:),50, 'MarkerFaceColor', '#ed7023', 'MarkerEdgeColor', '#ed7023')
    hold on
end
X_pos_secondBar =x+b(2).XOffset

for i = 1:size(scatterPoints3,1)
    s(3) = scatter(x+b(3).XOffset, scatterPoints3(i,:),50, 'MarkerFaceColor', '#ed7023', 'MarkerEdgeColor', '#ed7023')
    hold on
end
X_pos_thirdBar =x+b(3).XOffset 

%%code for grey region
xValues = reshape ([ X_pos_firstBar ; X_pos_secondBar; X_pos_thirdBar], size(X_pos_firstBar,2), [] );
xValues = xValues(:)';

upper_line= repelem(greyRegionPoints(2,:), 2); %%repeats these points so that the region behind each of the three bars has the same value (gives straight line)
lower_line = repelem(greyRegionPoints(3,:), 2);

h = figure;
x = 1:numel(Behaviours);
yValues = norm_WT_obj_SH_allInfo(1, :); %straight line
plot(x, yValues, 'k-');  %plot straight line
% ylim([0, ((max(max(norm_WT_obj_SH_allInfo))*1.5))]);
ylim([0 inf])
hold on;
plot(xValues, upper_line, 'LineWidth', 0.5, 'Color', 'white'); %plot line that should be upper interval line
hold on;
plot(xValues, lower_line, 'LineWidth', 0.5 , 'Color', 'white'); %plot line that should be lower interval line
x2 = [xValues, fliplr(xValues)];
inBetween = [upper_line, fliplr(lower_line)];
f= fill(x2, inBetween, 'k');
set(f,'facealpha',.1)
set(f,'edgecolor','white');
set(gca,'TickDir','out');
hold on;

Answer 2

[Gaurav Garg]

Hey Amy,

The grey shaded region seem to have varying y-values for the respective x-values.

What is evident from your code is that norm_WT_std2_SH_allInfo is an array of dimensions m*3, and borders of the shaded region are plotted using the second and third columns of the array. So, I would suggest you to look into the values in this array and change them (if needed) to make your grey shaded region to be a straight horizontal region.

The needed changes can be understood as -

You can plot any line parallel to x-axis if the y-value at each x-point for the line is 0.