So that your time can be spent productively working
on the problem set as opposed to struggling with MATLAB® and
statistical quandaries, below are a few pieces of information that you might
find helpful.
·
The MATLAB® function that generates Gaussian noise is randn. By default, randn creates Gaussian
random numbers with zero mean and standard deviation of one.
·
To scale the standard deviation of a Gaussian random variable by some
factor, k, you simply need to multiply by k. For example, if you want 1000 random numbers
from a Gaussian distribution with a standard deviation of 5, in MATLAB®,
you would simply write n = 5*randn(1000,1). This creates a column vector of 1000 random numbers whose
standard deviation is 5 and whose mean is zero.
·
The MATLAB® function for a Uniformly distributed RV is rand. By default, rand generates Uniformly
distributed random numbers between 0 and 1.
Consequently, the mean value of a set of Uniformly distributed RVs
generated by rand is 0.5. It is
also easily shown that their standard deviation is . Thus, to properly
generate uniformly distributed RVs with zero mean and standard deviation k,
you must perform two operations. First,
you must de-mean the random numbers by subtracting their expected value,
0.5. Second, you must multiply the
random numbers by
to achieve the
desired standard deviation. For
example, suppose you want a vector of 1000 Uniformly distributed RVs of mean
zero and standard deviation 5. In
MATLAB®, you would write n = 5*(6/sqrt(3))*(rand(1000,1) - 0.5);