The noise voltage in an electric circuit can be modeled as a gaussian random variable with a mean equal to zero and a variance equal to 10- 1. what is the probability that the value of the noise exceeds 10~4? what is the that it exceeds 4 x 10-4? what is the probability that the noise value is between-2 x 10-4 and 10-4? 2. given that the value of the noise is positive, whatis the probability that it exceeds 10-4? 3. this noise passes through a half-wave rectifier with characteristics 0, xs0 find the pdf of the rectified noise by first finding its cdf. why can we not use the general expression in equation (5.1.11)? 4. find the expected value of the rectified noise in the previous part. 5. now assume that the noise passes through a full-wave rectifier defined by g(x) - xl. find the density function of the rectified noise in this case. what is the expected value of the output noise in this case?