| SRI {assocInd} | R Documentation |
Simple Ratio Index
Description
Calculates the simple ratio index
Usage
SRI(x, Ya, Yb, Yab)
Arguments
x |
Number of times individuals a and b were observed together |
Ya |
Number of times individual a was observed without b |
Yb |
Number of times individual b was observed without a |
Yab |
Number of times individuals a and b were observed at the same time but not associating |
Details
The simple ratio index calculates the probability that two individuals are observed together given that one has been seen. This index is widely used in animal social network analysis.
Value
Returns two elements: the estimated association strength and the standard error of the estimate.
Author(s)
William Hoppitt <W.J.E.Hoppitt@leeds.ac.uk> Damien Farine <dfarine@orn.mpg.de>
References
Hoppitt, W. & Farine, D.R. (in prep) Association indices for quantifying social relationships: how to deal with missing observations of individuals or groups.
Examples
# Simulated values (all = 10)
x <- ya <- yb <- yab <- 10
# Calculate simple ratio index
SRI(x,ya,yb,yab)