Left panels: normalized metallicity distribution for the giant stars with M_⋆ > 1.5 M_⊙ (top panel) and M_⋆< 1.5 M_⊙ (bottom panel). Right panels: same histograms as in the left panels but including the giant control sample from Maldonado et al. (2013). In all cases, the red solid line corresponds to the sample of giant stars with planets, whereas the black dashed line represents the giant control sample without planets. Median values of the distributions are indicated with vertical lines.