assocInd (version 1.0.1)

SRI: 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

Value

Returns two elements: the estimated association strength and the standard error of the estimate.

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.

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)