How do I add a line, or a linear regression from cftool, to a scatter graph?

Hi, I have a scatter graph that consists multiple arrays of information. Also I have a linear regression,which I generated its code, but when I launch the program it gives me 2 graphs: the scatter one, and the regression one in 2 different outputs. Of course I used the hold ons, both for the scatter graph (which works well) and for the regression graph, but it doesn't add it right. How do I add it together? That's how it looks:

Thanks very much in advance!

Answer 1

[sloppydisk]

You could use copyobj:

% data 
n = 200;
x = 1:n;
y = x+25*rand(1, n);

figure(1)
% handle to first axis
ax1 = gca;
scatter(y, x)

b = x'\y';
figure(2)
% handle to second plot
h2 = plot(b*x, x);

% copy line object from second plot to axis from first plot
copyobj(h2, ax1);

[Roee Ben Shlomo]

I'm sorrry but I'm not sure how to use it. I'm very new to Matlab. Is it a function? How do I use it with my own code? As you can see I have my scatter graphs well organized, I just need the line creatFit2(timesForRegression,Velocity2) to appear on the same graph.

[sloppydisk]

Ah I may have overcomplicated things by not reading your question carefully, my bad. I assume you create a new figure inside createFit2 by calling

figure(2)

or

figure

, if you remove that line any new plot should go to the existing figure created earlier by your scatter call.

[Roee Ben Shlomo]

Thank you very much, it works! Another thing, if I want to add another line which I have the formula for( y=-88.69x +180.5 if it matters), how do I do it? since the line I added ends when my data ends, but I want it to continue all the way.

[sloppydisk]

You can just do another plot command with new x-values. For example if you want the line from zero to five:

x = [0 5]; y = -88.69*x +180.5; plot(x, y)

Though I am sure you could have figured this out without me by reading

doc plot