Top panel: distribution of HERMES σ_j(RV) per star j of the reference sample (R) of CoRoT/Kepler K giants. Bottom: F2_j distribution for the same sample. In black is drawn the full sample, and in red the sample with binaries removed (F2 ≥ 3.0), which leads to an almost perfect match between the binary-free observed F2 distribution (red curve) and the expected 𝒩(0, 1) normal-reduced distribution (blue curve).