We generalise the procedure for joint estimation of cosmological parameters to allow freedom in the relative weights of various probes .
This is done by including in the joint Likelihood function a set of ‘ Hyper-Parameters ’ , which are dealt with using Bayesian considerations .
The resulting algorithm is simple to implement .
We illustrate the method by estimating the Hubble constant H _ { 0 } from the recent Cosmic Microwave Background experiments Boomerang and Maxima .
For an assumed flat \Lambda -CDM model with fixed parameters ( n = 1 , \Omega _ { m } = 1 - \lambda = 0.3 , \Omega _ { b } h ^ { 2 } = 0.03 , { Q _ { rms } } = 18 \mu K ) we solve for a single parameter , H _ { 0 } = 79 \pm 4 km/sec/Mpc ( 95 % CL , random errors only ) , slightly higher but still consistent with recent results from Cepheids .
We discuss how the ‘ Hyper-Parameters ’ approach can be generalised for a combination of cosmic probes , and for other priors on the Hyper-Parameters .