Left panel: 2D distribution of the frequency and amplitude deviations between the prewhitened and the injected values for 1000 artificial modes of constant amplitude. S/N denotes the signal-to-noise ratio of the injected signals and the deviations have been normalized by the 1σ error, σ_A and σ_f, derived from the prewhitening procedure implemented in the code Felix. The 2D distribution is also projected into 1D histograms (frequency and amplitude) to be compared with the Normal Distribution, plotted as a red solid curve. Right panel: same as above but for 1000 modes with random amplitudes. The injected modes are divided into three groups of S/N in the ranges [5,15], (15,25], and (25,60], respectively (represented by three different colors and symbols).