A zero-mean sequence, has covariance function We would like to estimate m by observing T consecutive samples of the process. How large must T be, in order for the standard deviation of the estimate...

A zero-mean sequence,

has covariance function

We would like to estimate m by observing T consecutive samples of the process. How large must T be, in order for the standard deviation of the estimate to be less than 0.1? You can make appropriate approximations.