EV.Tcomb {nnspat}

Expected Value for Cuzick & Edwards T_{comb} Test Statistic

Description

This function computes the expected value of Cuzick & Edwards T_{comb} test statistic in disease clustering, where T_{comb} is a linear combination of some T_k tests.

The argument, n_1, is the number of cases (denoted as n1 as an argument). The number of cases is denoted as n_1 to match the case-control class labeling, which is just the reverse of the labeling in Cuzick and Edwards (1990).

The argument klist is the vector of integers specifying the indices of the T_k values used in obtaining the T_{comb}.

The argument sig is the covariance matrix of the vector of T_k values used in Tcomb, and can be computed via the the covTcomb function.

See page 87 of (Cuzick and Edwards (1990)) for more details.

Usage

EV.Tcomb(n1, n, klist, sig)

Arguments

n1

Number of cases

n

A positive integer representing the number of points in the data set

klist

list of integers specifying the indices of the T_k values used in obtaining the T_{comb}.

sig

The covariance matrix of the vector of T_k values used in Tcomb

Value

Returns the expected value of the T_{comb} test statistic

Author(s)

Elvan Ceyhan

References

Cuzick J, Edwards R (1990). “Spatial clustering for inhomogeneous populations (with discussion).” Journal of the Royal Statistical Society, Series B, 52, 73-104.

See Also

Tcomb, and ZTcomb

Examples

n<-20  #or try sample(1:20,1) #try also n<-50, 100
Y<-matrix(runif(3*n),ncol=3)
cls<-sample(0:1,n,replace = TRUE)  #or try cls<-rep(0:1,c(10,10))
n1<-sum(cls==1)

kl<-sample(1:5,3) #try also sample(1:5,2)
kl
sig<-covTcomb(Y,n1,kl)
EV.Tcomb(n1,n,kl,sig)