Fig. 2. Observed and estimated probabilities of feeding (together with 95% confidence intervals) as a function of starfish size (diameter in cm), time of day and depth. Hollow and filled circles and associated lines indicate day and night, respectively. For (a) the depth is ,3 m, for (b) .3 m, and for (c) the depths are pooled. The estimated probability of feeding as a function of size is shown in (d) (solid line), together with the biased estimate (dotted line).