Hi Jostro,
I created a dummy data based on the "dummy_rt" you provided and used the code provided. It worked and generated a "violin" plot. Following is the code used for data generation:
dummy_rt = cell(10, 3);
dummy_rt(:, 1) = num2cell(750 + (3000-750).*rand(10, 1)); % Values selected from gramm code
dummy_rt(1:5, 2) = {'a'};
dummy_rt(6:10, 2) = {'b'};
dummy_rt([1,2,5,6,7], 3) = {'c'};
dummy_rt([3,4,8,9,10], 3) = {'d'};
The error you are facing might be due to data problems. You can try these as troubleshooting steps:
- Check that the data within "dummy_rt" is consistent in terms of size and format. Ensure that the first vector is numeric and the remaining vectors are categorical or cell arrays of strings with consistent dimensions across all rows.
- If "dummy_rt" contains cell arrays of strings for the factors, consider converting them to categorical variables, which might be handled more consistently by the plotting functions.
- Instead of changing values of the dependent variable, try simplifying your plot by removing the 'color' argument or by plotting only the violin or boxplot to see if one of these elements is causing the issue.
As a workaround, you could try creating the boxplot manually using MATLAB's built-in "boxplot" function and "violin" from file-exchange to see if the issue persists outside of "Gramm". Following is a sample code you can tinker around:
fac1_str = string(dummy_rt(:, 2));
fac2_str = string(dummy_rt(:, 3));
groups = fac1_str + "_" + fac2_str;
YVar = cell2mat(dummy_rt(:, 1));
figure;
violin(YVar, groups); % File Exchange function
hold on;
boxplot(YVar, groups, 'Widths', 0.2, 'Notch', 'on', 'Colors', 'k');
hold off;
ylim([750 3000]);
title('Reaction Times for Pair Recognition (N = 48)', 'FontSize', 10);
xlabel('Type of Pairing');
ylabel('Reaction time in ms');
You can check the following documentation to learn more about each function:
- categorical: https://www.mathworks.com/help/matlab/ref/categorical.html
- boxplot: https://www.mathworks.com/help/stats/boxplot.html
You can try this file exchange link to plot a "violinplot":
Hope this helps!
