How to creat noisy copies of vector?

I should generate values of a linear function f(x) = ax + b for the x variable taking on values from the interval <-4,10> with step 0.1.

x = -4:0.1:10 ; % i did it

and to create two noisy copies: Y1, and Y2 by adding pseudo-random noise from normal distribution: one with a variance v1 = 0.1, the other with v2 = 1. How can I do that?

Answer 1

[Bora Eryilmaz]

x = -4:0.1:10;

v1 = 0.1;
r1 = sqrt(v1).*randn(size(x));
Y1 = x + r1;
var(r1) % Should be approximately 0.1

ans = 0.0992

v2 = 1;
r2 = sqrt(v2).*randn(size(x));
Y2 = x + r2;
var(r2) % Should be approximately 1.0

ans = 1.0422

plot(x)
hold on
plot(Y1)
plot(Y2)