# EV.Tcomb: Expected Value for Cuzick & Edwards T_{comb} Test Statistic In nnspat: Nearest Neighbor Methods for Spatial Patterns

 EV.Tcomb R Documentation

## 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 \insertCitecuzick:1990;textualnnspat.

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 (\insertCitecuzick:1990;textualnnspat) 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

Elvan Ceyhan

### References

\insertAllCited

`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)

```

nnspat documentation built on Aug. 30, 2022, 9:06 a.m.