MATLAB Answers

Fit a line to data using regress

46 views (last 30 days)
Nicholas Deosaran
Nicholas Deosaran on 25 Sep 2020 at 1:16
Edited: Adam Danz on 28 Sep 2020 at 16:31
Hey all, I am trying to use a new matlab function "regress" and would like some help on how to use it to fit a line.
below is my code that I have so far, but lost on how to use the "regress" function.
x = 0:0.1:10;
n = 0;
noise = n*rand(1,length(x));
y = 2*x+1+noise;
figure(1);
plot(x,y,'d')

  0 Comments

Sign in to comment.

Answers (1)

Adam Danz
Adam Danz on 25 Sep 2020 at 1:36
Edited: Adam Danz on 25 Sep 2020 at 2:23

  2 Comments

Nicholas Deosaran
Nicholas Deosaran on 25 Sep 2020 at 2:07
Oh okay, I see.
and to plot that line on the axis..will it be
x = 0:0.1:10;
n = 0;
noise = n*rand(1,length(x));
y = 2*x+1+noise;
b = regress(y(:),x(:));
plot(x,y,'d') %plot as diamonds
hold on
plot(b,y)
hold off
is that correct?
Adam Danz
Adam Danz on 25 Sep 2020 at 2:20
No, b is just the slope if you've used the syntax from my answer.
If you want to plot the regression line you'll need the y-intercept term. To get the y-intercept term you need to add a column of 1s to x.
b = regress(y(:),[ones(size(x(:))),x(:)]);
b is a 2x1 vector containing the [intercept; slope];
Use refline(b(2),b(1)) to add the regression line.
Or, check out lsline.
Or, check out polyfit(x,y,1) along with refline.

Sign in to comment.

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by