vcovEmax {clinDR}

Extract Emax model variance-covariance matrix for ML estimates

Description

Extract Emax model variance-covariance matrix for ML estimates

Usage

	## S3 method for class 'fitEmax'
vcov(object, ...)
	## S3 method for class 'emaxsim'
vcov(object, ...)

Arguments

object

Output of Emax fitting and simulation functions

...

None additional inputs supported

Value

Variance-Covariance matrix for the MLE estimates of the parameters from fitEmax. The lower half of the variance-covariance matrix for the estimated parameters stored as a vector in column-major order for each emaxsim simulation. The vc matrix has 16,9, or 4 elements depending on fitType.

Author(s)

Neal Thomas

See Also

fitEmax, emaxsim

Examples

doselev<-c(0,5,25,50,100,350)
n<-c(78,81,81,81,77,80)

### population parameters for simulation
e0<-2.465375 
ed50<-67.481113 

dtarget<-100
diftarget<-9.032497
emax<-solveEmax(diftarget,dtarget,log(ed50),1,e0)

sdy<-8.0
pop<-c(log(ed50),emax,e0)    
dose<-rep(doselev,n)
meanlev<-emaxfun(dose,pop)  

y<-rnorm(sum(n),meanlev,sdy)

testout<-fitEmax(y,dose,modType=4)
vcov(testout)