Fig. 9 in Patterns of drilling predation of cassid gastropods preying on echinoids from the middle Miocene of Poland

Fig. 9. Intensities of drilling predation observed within particular samples (A) and facies (B). Confidence intervals for large samples (30 specimens or more) p (1 − p) computed from the formula p ± 1.96, where p denotes the proportion of one kind of fossil observed in the collection of n specimens (Łomnicki n 1995). Confidence intervals for small samples (less than 30 specimens) derived from Weber (1964: Table 8a).