I want to get a linear curve fitting for each line in graph

I want to get a linear curve fitting for each of the data point separately in the graph below

Answer 1

[dpb]

The Statistics Toolbox has a function lsline that does this automagically but for some reason that is totally unexplicable to me, they've neutered it so it ignores any/all lines that are not just points/markers. Dunno why they think use cases like this aren't common as well.

But a workaround could be

hAx=gca;  hL=hAx.Children;                                    % retrieve the axes and line handles
hF=arrayfun(@(h)fitlm(h.XData,h.YData,"linear"),hL,'Uni',0);  % fit each in turn, save fit handles
LS=get(hL,'Linestyle');                                       % get the used linestyle to put back
MK=get(hL,'Marker');                                          % and marker, too
set(hL,{'Linestyle'},{'none'},'Marker',{'o'})                 % turn line off, add marker
hLSqL=lsline(hAx);                                            % now add the LS line
set(hL,{'Linestyle'},LS,{'Marker'},MK)                        % put back the original line, marker
% optional instead to keep a marker -- can be hard to see with both lines where data are
%set(hL,{'Linestyle'},LS,{'Marker'},{'none'})                 % put back the original line, leave marker

Alternatively, you can (and I'd recommend) use the X,Y data you had when you drew the plot and follow a similar route but use those data directly.