# geary.mc: Permutation test for Geary's C statistic In spdep: Spatial Dependence: Weighting Schemes, Statistics

 geary.mc R Documentation

## 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=NULL, alternative="greater",

### 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 default NULL, use global option value; if TRUE assign zero to the lagged value of zones without neighbours, if FALSE assign NA alternative a character string specifying the alternative hypothesis, must be one of "greater" (default), or "less"; this reversal corresponds to that on geary.test described in the section on the output statistic value, based on Cliff and Ord 1973, p. 21 (changed 2011-04-11, thanks to Daniel Garavito). spChk should the data vector names be checked against the spatial objects for identity integrity, TRUE, or FALSE, default NULL to use get.spChkOption() adjust.n default TRUE, if FALSE the number of observations is not adjusted for no-neighbour observations, if TRUE, the number of observations is adjusted return_boot return an object of class boot from the equivalent permutation bootstrap rather than an object of class htest

### Value

A list with class htest and mc.sim containing the following components:

 statistic the value of the observed Geary's C. parameter the rank of the observed Geary's C. p.value the pseudo p-value of the test. alternative a character string describing the alternative hypothesis. 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

### Author(s)

Roger Bivand Roger.Bivand@nhh.no

### References

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

geary, geary.test

### Examples

data(oldcol)
sim1 <- geary.mc(COL.OLD\$CRIME, nb2listw(COL.nb, style="W"),
nsim=99, alternative="less")
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)

spdep documentation built on March 7, 2023, 7:27 p.m.