Abundance differences (M 67-1194 − group mean) where the means are taken for stars in the different groups, Main-sequence stars, Turn-off point stars and Subgiant stars, respectively. The solar-twin line of Meléndez et al. (2009) is indicated (red dashed). The panel in the bottom displays the differences Sun − M 67-1194. Error bars in the upper three panels represent the RMS errors in the group means (σ/). In the bottom panel the error bars represent line-to-line scatter.