Likelihood distribution for models with cosmological constant from COBE data

Using COBE Differential Microwave Radiometer (DMR) 4 yr data, we find a gen eral expression yielding the likelihood distribution in the three-dimension al parameter space spanned by the spectral index n, the spectral amplitude a(10), and the false-vacuum density parameter Omega (Lambda). Using such si mple expression, the range of possible normalizations within a given likeli hood interval from top-likelihood normalization is readily found, with fair approximation, for any model with total density parameter Omega (0) = 1 an d assigned n and Omega (Lambda).