How to add errors when standard deviation is given?

I have a dataset consisting of 50 rows. How do i add noise when standard deviation is given as i)2 ii) 3% of true value

Answer 1

[Chinmay Anand]

Check out this answer

https://www.mathworks.com/matlabcentral/answers/115070-adding-noise-with-certain-standard-deviation-to-uncorrupted-data