Comparison between the simulated and real data for τ  Ceti (HD 10700), HD 20794, HD 192310, and HD 85512. For each star, the simulated data are generated with the same calendar as the observed measurements. We then compute the rms of the RVs, the BIS SPAN, the FWHM, and the log () for chunks of ten consecutive days each, including at least seven observations. Each subplot shows the histogram of the rms computed based on the observed (blue) and simulated (red) data, with the corresponding median highlighted by the dashed vertical lines and its value reported in the legend. The agreement between the histograms and the median values demonstrates that the simulated data that include granulation signal, oscillation signal, and instrumental noise are similar to the real observations performed with HARPS.