Simulations of a chunk of PSD for the peak significance test in a red giant. The top panel shows the case of a simulation containing only a flat noise component, while the bottom panel shows a simulation including an oscillation peak with its characteristic Lorentzian shape. The black thick line represents the resulting fit as computed by Diamonds  (using ℳ_A in the top panel and ℳ_B in the bottom panel), with median values for each parameter.