spdep (version 0.1-2)

geary.mc: Permutation test for Geary's C statistic

Description

A permutation test for Geary's C statistic calculated by using nsim random permutations of x for the given spatial weighting scheme, to establish the rank of the observed statistic in relation to the nsim simulated values.

Usage

geary.mc(x, listw, nsim, zero.policy=FALSE)

Arguments

x

a numeric vector the same length as the neighbours list in listw

listw

a listw object created for example by nb2listw

nsim

number of permutations

zero.policy

if TRUE assign zero to the lagged value of zones without neighbours, if FALSE assign NA

Value

• A list with class htest containing the following components:
• statistic
  the value of the observed Geary's C.
• parameter
  the rank of the observed Geary's C.
• method
  a character string giving the method used.
• data.name
  a character string giving the name(s) of the data, and the number of simulations.
• res
  nsim simulated values of statistic, final value is observed statistic

References

Cliff, A. D., Ord, J. K. 1981 Spatial processes, Pion, p. 63-5.

See Also

geary, geary.test

Examples

data(oldcol)
sim1 <- geary.mc(COL.OLD$CRIME, nb2listw(COL.nb, style="W"), nsim=99)
sim1
mean(sim1$res)
var(sim1$res)
summary(sim1$res)
colold.lags <- nblag(COL.nb, 3)
sim2 <- geary.mc(COL.OLD$CRIME, nb2listw(colold.lags[[2]], style="W"),
 nsim=99)
sim2
summary(sim2$res)
sim3 <- geary.mc(COL.OLD$CRIME, nb2listw(colold.lags[[3]], style="W"),
 nsim=99)
sim3
summary(sim3$res)