问题
I am trying to get the residuals for the scatter plot of two variables. I could get the least squares linear regression line using lsline function of matlab. However, I want to get the residuals as well. How can I get this in matlab. For that I need to know the parameters a and b of the linear regression line
ax+b
回答1:
Use the function polyfit to obtain the regression parameters. You can then evaluate the fitted values and calculate your residuals accordingly.
Basically polyfit performs least-squares regression for a specified degree N which, in your case will be 1 for straight line regression. The regression parameters are returned by the function and you can use the other function polyval to get the fitted values from the regression parameters
回答2:
If you have the curve fitting toolbox, type cftool and press enter and the GUI will appear.
You can use this tool to find a linear polynomial fit for a given data set, as well as many other fits.
来源：https://stackoverflow.com/questions/11209974/linear-regression-line-in-matlab-scatter-plot