Mass (top panel) and density (bottom panel) are given as a function of radius for all known exoplanets with radius R < 4 R _⊕ that have radial velocity mass measurements (shown in gray). The size of the points (excluding Kepler-102d and Kepler-102e) scales inversely with the error of their mass measurement. The black line shows the mass–radius relation from Weiss & Marcy (2014). The density–radius curves for planets of solid iron, solid rock, and an Earth-like composition from Zeng et al. (2019) are shown, as well. Kepler-102d and Kepler-102e (K-102d and K-102e) are shown with their previous mass measurements, and for each model we explore in this paper (individual vs. combined data sets, with and without Gaussian process, GP, stellar noise modeling). For Kepler-102d, the marker for the combined data set without GP, as well as the marker for HARPS-N with GP, fall behind the marker for the full data set with GP.