Hello Hanna,
Recently for one of my projects, I also wanted to add statistical significance indicators (sigmas) between bars to highlight significant differences. When reading problem you were facing, I understood that you want to add sigmas between bars of different groups (methods under which force measurements taken) for each participant using sigstar function.
I found out that to use sigstar method you need to download repository from MATLAB File Exchange since it is not built in function in MATLAB. Here is the repository link that can be useful
Once you download the repository, extract the downloaded files and move "sigstar.m" file to your MATLAB working directory.
we can import it using "addpath" function as shown below
addpath("sigstar.m")
Here I assume that you are using p-values from your statistical tests to determine the significance levels (e.g., p < 0.05, p < 0.01, etc.). Also I am using one asterisk (*) between the bars to indicate p < 0.05 and two asterisks (**) between the red and yellow bars to indicate p < 0.01.
Here is an example using sample data to add significance indicators to the plot
% Sample data for seven participants, each with three measurements (FP, NW, SW)
data = [
1500, 1400, 1300; % Participant 1
1600, 1550, 1500; % Participant 2
1700, 1650, 1600; % Participant 3
1800, 1750, 1700; % Participant 4
1900, 1850, 1800; % Participant 5
2000, 1950, 1900; % Participant 6
2100, 2050, 2000; % Participant 7
];
% Colors for the bars
colors = [0 0 1; 1 0 0; 1 1 0]; % Blue, Red, Yellow
% Create the bar chart
figure;
b = bar(data, 'grouped');
for k = 1:size(data, 2)
b(k).FaceColor = colors(k, :);
end
% Add legends
legend({'FP', 'NW based Calibration', 'SW based Calibration'}, 'Location', 'northwest');
% Example significance levels (assuming them as results from statistical tests)
% These are hypothetical p-values for comparisons between different bars for each participant
sigLevels = [
0.03, 0.02; % Participant 1
0.04, 0.01; % Participant 2
0.05, 0.03; % Participant 3
0.02, 0.01; % Participant 4
0.03, 0.04; % Participant 5
0.01, 0.02; % Participant 6
0.05, 0.03; % Participant 7
];
% Define pairs for significance indicators
sigPairs = {};
pValues = [];
for i = 1:size(data, 1)
if sigLevels(i, 1) < 0.05
sigPairs{end+1} = [i-0.2, i]; % Pair for FP vs NW
pValues(end+1) = sigLevels(i, 1);
end
if sigLevels(i, 2) < 0.05
sigPairs{end+1} = [i, i+0.2]; % Pair for NW vs SW
pValues(end+1) = sigLevels(i, 2);
end
end
% Add significance indicators using sigstar
sigstar(sigPairs, pValues);
% Customize the plot
ylim([0, 2200]); % Adjust y-axis limit to fit significance indicators
xticks(1:7);
xticklabels({'Participant 1', 'Participant 2', 'Participant 3', 'Participant 4', 'Participant 5', 'Participant 6', 'Participant 7'});
ylabel('Force (N)');
xlabel('Participants');
title('Force Measurements for Participants with Significance Indicators');
hold off;
I have tested above solution on MATLAB R2024a version.
Please let me know if this helps in your problem. Thanks.
