graphing mean and SD of time-course data (grouping based on group number and time)

Hello,

I am trying to graph the mean and SD deviation of time-course data. I need to use the mean and SD based on the group number at each time point. I will then overlay this time-course data with some simulations I've performed. Can anyone help provide me with the code to do this?

Thanks in advance!

Answer 1

[Pavan Sahith]

Hi Brett,

As per my understanding, you want to plot the mean and standard deviation of data based on group number at each time point. Additionally you want to overlay this time-course data with some simulations.

• So, I assumed a simple time-course data example with 10 elements and some sample simulation data for better understanding.

time = [1 1 2 2 3 3 4 4 5 5]; % Time points
group = [1 1 1 2 2 2 3 3 3 4]; % Group numbers
data = [10 12 9 11 8 10 7 9 6 8]; % Time-course data

Which means,

at time=1, data =10 if it is from group =1 (mapping 1st element in all 3 arrays)

at time=3, data =8 if it is from group =2 (mapping 5th element in all 3 arrays)

• To seperate the groups and time point arrays , you can use unique ,Please refer the below attached MathWorks Documentation links for more information on unique.https://in.mathworks.com/help/matlab/ref/double.unique.html

uniqueGroups = unique(group);
uniqueTime = unique(time);

%initializing the mean and std matrices with all 0s  
meanData = zeros(numel(uniqueGroups), numel(uniqueTime));
stdData = zeros(numel(uniqueGroups), numel(uniqueTime));

• To find the mean and standard deviation you can use mean() and std() , Please refer the following MathWorks Documentation links for more information

mean - https://in.mathworks.com/help/matlab/ref/mean.html

standard deviation - https://in.mathworks.com/help/matlab/ref/timeseries.std.html

% populating the matrices using mean and std functions
for i = 1:numel(uniqueGroups)
    for j = 1:numel(uniqueTime)
        idx = group == uniqueGroups(i) & time == uniqueTime(j);
        meanData(i, j) = mean(data(idx));
        stdData(i, j) = std(data(idx));
    end
end

• To plot mean and standard deviation based on groups at each time point , you can use errorbar as standard deviation is defined as a measure which shows how much variation (such as spread, dispersion, spread,) from the mean exists. For more details, please refer the following MathWorks Documentation link on errorbar-https://in.mathworks.com/help/matlab/ref/errorbar.html

figure;
hold on;
for i = 1:numel(uniqueGroups)
    errorbar(uniqueTime, meanData(i, :), stdData(i, :), 'o-', 'LineWidth', 1.5);
end

% labelling the axes and setting a title
xlabel('Time');
ylabel('Data');
title('Mean and Standard Deviation of Time-Course Data');
grid on;

• To overlay the simulations ,please refer to the following sample code which is using sample simulation data to plot.

% Overlay simulations with sample data
simulations = [9.5 11 8.5 10.5 7.5]; % Simulated data
timeSimulations = [1 2 3 4 5]; % Time points for simulations
groupSimulations = [1 2 3 4 1]; % Group numbers for simulations
for i = 1:numel(uniqueGroups)
    idx = groupSimulations == uniqueGroups(i);
    plot(timeSimulations(idx), simulations(idx), 'r--', 'LineWidth', 1.5);
end
legend('Group 1', 'Group 2', 'Group 3', 'Group 4','Simulations');

Please execute the MATLAB code to see the plot for the given sample data.