Method of Parameter class (access via parameter$<function name>, where parameter is an object initialized by initializeParameterObject). Calculate variance of noise offset parameter used when fitting model with empirical estimates of synthesis rates (ie. withPhi fits)
mixture index to use. Should be number between 0 and n-1, where n is number of mixtures
number of samples over which to calculate variance
If TRUE, should calculate variance using unbiased (N-1). Otherwise, used biased (N) correction
returns variance for noise offset