2.21 When introduced into an area containing both fine and coarse sand, antlions are thought to prefer to dig burrows in fine sand, but also to avoid other ant-lions. The data below describe the results of 62 experiments in which either 3 or 4 ant-lions are introduced into an area with fine and coarse sand, and form a subset of the data in Table 1.10. Explain how you would describe the data by means of a binomial model with probability p of burrowing in fine sand.

Number of ant-lions Total number Number of ant-lions introduced of experiments burrowing in fine sand 01234 3 32 0 7 24 1 4 30 0 3 17 10 0 Obtain the maximum-likelihood estimate p, and use it to form expected values corresponding to the observed values in the above table.

Without formally computing a goodness-of-fit statistic, discuss the goodness of fit of the binomial model to the data by visually comparing observed and expected cell numbers in the above table.