How can I add noise to linear graph
21 views (last 30 days)
Show older comments
I have 100 sample points and I'm using y=mx+c to create 1d line and add gaussian noise using randn the attached graph is the result that I got when I tried the first code and when I try the second code I get straight line I think there is something wrong with my plot but I'm not sure where ?
code1
sample = 100;
x = linspace(-5,5);
y= 1.6 * x +6;
dataset = randn(sample,2);
figure
plot(dataset,y)
axis([-8 7])
code2
sample = 100;
x = linspace(-5,5);
y= 1.6 * x +6;
dataset = y*randn(sample,2);
figure
plot(dataset)
axis([-8 7]);
this is the result that I want to get
0 Comments
Accepted Answer
jgg
on 21 Jan 2016
Edited: jgg
on 21 Jan 2016
You never added the random noise to your dataset:
sample = 100;
x = linspace(-5,5);
y= 1.6 * x +6;
r = randn(2,sample);
figure
plot(x,r(1,:)+y)
hold on
plot(x,r(2,:)+y)
The actual outcome value is y + r(i,:) not just y; you also are plotting it incorrectly before.
2 Comments
jgg
on 21 Jan 2016
Yes. Let's code it up a little more clearly since you want to fit something too:
sample = 100;
x = linspace(-5,5);
y= 1.6 * x +6;
r = randn(2,sample);
y_noise = y + r(1,:);
X = [ones(1,length(x)); x];
beta = regress(y_noise',X');
y_fitted = beta(1) + x*beta(2);
figure
plot(x,y_noise)
hold on
plot(x,y_fitted)
This fits a linear regression curve to the noisy data using the regress function with an intercept. The coefficients are in beta.
If this answer solved your problem, please help others find it by accepting it.
More Answers (0)
See Also
Categories
Find more on Descriptive Statistics in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!