derive slope from plotInteraction

Dear experts, I would like to extract the slopes of the lines you see when you use the plotinteraction command on multiple linear regression analysis. For example, I'm attaching the plotInteraction from the Mathworks tutorial on linear regression (https://it.mathworks.com/help/stats/linearmodel.plotinteraction.html). How can I derive the slope of the purple, yellow and red lines of the attached figure?

Answer 1

[Mathieu NOE]

hello

FYI, you can access any figure underlying data (and of course compute the slope)

openfig('myfig.fig');
set(gcf, 'Visible','off')
Ax = gca;                                                   % Another Option
Lines =  findobj(Ax, 'Type','line');                        % Return Handles To All 'Line' Objects
x =  Lines.XData(:);                                        % Independent Variable (Force Column Vector With '(:)')
y =  Lines.YData(:);                                        % Dependent Variable  (Force Column Vector With '(:)')
Figure_Table = table(x,y, 'VariableNames',{'X values','Y values'})