# achisq.boot: Bootstrap Replicates of Pearson's Chi-square Statistic In DCluster: Functions for the Detection of Spatial Clusters of Diseases

 achisq.boot R Documentation

## Bootstrap Replicates of Pearson's Chi-square Statistic

### Description

Generate bootstrap replicates of the Pearson's Chi-square statistic (function achisq.stat), by means of function boot from boot library. Notice that these functions should not be used separately but as argument statistic when calling function boot.

achisq.boot is used when performing a non-parametric bootstrap.

achisq.pboot is used when performing a parametric bootstrap.

### Usage

``````achisq.boot(data, i, ...)
achisq.pboot(...)
``````

### Arguments

 `data` A dataframe containing the data, as specified in DCluster manpage. `i` Permutation generated by the non-parametric bootstrap procedure. `...` Additional arguments passed when performing a bootstrap.

### Value

Both functions return the value of the statistic.

### References

Potthoff, R. F. and Whittinghill, M.(1966). Testing for Homogeneity: I. The Binomial and Multinomial Distributions. Biometrika 53, 167-182.

Potthoff, R. F. and Whittinghill, M.(1966). Testing for Homogeneity: The Poisson Distribution. Biometrika 53, 183-190.

DCluster, boot, achisq, achisq.stat

### Examples

``````library(boot)
library(spdep)

data(nc.sids)

sids<-data.frame(Observed=nc.sids\$SID74)
sids<-cbind(sids, Expected=nc.sids\$BIR74*sum(nc.sids\$SID74)/sum(nc.sids\$BIR74))

niter<-100

#Permutation  model
chq.perboot<-boot(sids, statistic=achisq.boot, R=niter)
plot(chq.perboot)#Display results

#Multinomial model
chq.mboot<-boot(sids, statistic=achisq.pboot, sim="parametric", ran.gen=multinom.sim,  R=niter)
plot(chq.mboot)#Display results

#Poisson model
chq.pboot<-boot(sids, statistic=achisq.pboot, sim="parametric", ran.gen=poisson.sim,  R=niter)
plot(chq.pboot)#Display results

#Poisson-Gamma model
chq.pgboot<-boot(sids, statistic=achisq.pboot, sim="parametric", ran.gen=negbin.sim, R=niter)
plot(chq.pgboot)#Display results
``````

DCluster documentation built on Sept. 3, 2023, 5:07 p.m.