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. Author manuscript; available in PMC: 2016 Jul 1.
Published in final edited form as: Anim Behav. 2015 Jul 1;105:139–152. doi: 10.1016/j.anbehav.2015.04.012

Figure 2.

Figure 2

Model predicted mean (± 95% CI) z-transformed half-weight index of dyadic association in female chimpanzees in relation to z-transformed core area overlap and a dyadic grooming index that measures frequency of grooming in relation to observation time and opportunity (see text for definition of measures). For illustration purposes, we binned overlap z scores into below and above the median across all dyads and periods. As the grooming index was highly skewed towards zero values, we created three groups: no grooming recorded, and below and above median of all nonzero grooming indices in a given period. Numbers above or below error bars indicate the number of unique dyads in each group, across all periods.