Simulation of the PCCs and SCCs of Fe and Eu. PCC values of real and randomly generated Eu and Fe in stars with [Fe/H] < −2.5. See the text for this approach where λ relates to the fraction of category III events (where Eu is added independently without adding any Fe) versus the sum of category I+II+III events. Top panel: [Eu/Fe] < 0.3 is utilized for the upper limit of limited-r stars. Bottom panel: [Eu/Fe] < 0 is utilized as an upper limit for the same star type. In both cases a λ of about 2% seems to provide the best fit to the data.