Model comparison

• Z = p(D|M) =
• “marginal likelihood”, “evidence” …
• average likelihood over parameter space
• Z1/Z2:
• Probability for model M1 compared to M2
• Example:
• M1: wabs*pl – photo-el absorbed powerlaw
• M2: table{sphere}: includes Compton scattering

M1:

M2:

Z1/Z2 was 10

CDFS source 179

see Buchner+14