| MWI {assocInd} | R Documentation |
M-Weight index
Description
Calculates the m-weight index, a generalisation of the half-weight index correcting for individual identification error.
Usage
MWI(x, Ya, Yb, Yab, m)
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 |
m |
The correction term m (see details) |
Details
The m-weight index calculates the probability that two individuals are observed together given that one has been seen, but under the assumption that the probability of missing individuals a or b when they are together is equal to m times the probability of missing them when they are apart. This index can be used if prior information is available on the observation probability of individuals when they are together versus when they are apart (defined by the ratio m).
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
# Set m (here make the MWI equal to the SRI)
m <- 1.0
# Calculate m-weight index
MWI(x,ya,yb,yab,m)