Using polyfit for linear regression
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Hi guys, how do i get linear regression (p) of this X1 and Y1 values using polyfit?
I try but the X1 and Y1 keep changes back, expected i get like this graph in help window
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/374596/image.png)
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/374601/image.png)
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Answers (1)
Bjorn Gustavsson
on 8 Oct 2020
Your code looks OK. Your problem might be that you expect a result identical to the figure from the documentation.
However, you ask for a linear fit in your call to polyfit - note the difference between your call and the call in the documentation!
your call:
p = polyfit(x,y,1);
Call in documentation:
p = polyfit(x,y,7);
You ask for a first-order polynomial, the call from the documentation is for a 7-order polynomial. That's the difference.
HTH
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