the shape of Gaussian function is bell shaped, so mean=0 means the of the center of bell is located at ZERO in our horizontal axis.. and variance =1 means 50% span in both +ve and -ve axis...as shown in figure with RED line...
this is having a lot significance in communication systems, because we have to pass the fundamental freq of any signal, rest are the harmonics i.e. fundamental freq is located at zero point. here in communication system we want only the main band of signal and eliminating other harmonics so Gaussian filter can be applied..
secondly its also important in analysis of Noise..
u can search on google....for more detailed description.....Gaussian function - Wikipedia, the free encyclopedia
to become stationary in nature, it is mandatory for random process to have independent nature from time...i.e. statistical parameters viz mean,variance etc must not be affected by any shift in time...hence to be stationary random process mean is one of the parameter.....