mle2.GTDL {GTDL}

Maximum likelihood estimates of the GTDL model

Description

Maximum likelihood estimates of the GTDL model

Usage

mle2.GTDL(t, start, formula, censur, method = "BFGS")

Arguments

t

non-negative random variable representing the failure time and leave the snapshot failure rate, or danger.

start

Initial values for the parameters to be optimized over.

formula

The structure matrix of covariates of dimension n x p.

censur

censoring status 0=censored, a=fail.

method

The method to be used.

Value

Returns a list of summary statistics of the fitted GTDL model.

References

• Mackenzie, G. (1996) Regression Models for Survival Data: The Generalized Time-Dependent Logistic Family. Journal of the Royal Statistical Society. Series D (The Statistician). (45). 21-34.

See Also

optim

Examples

### Example 1

require(survival)
data(lung)

lung <- lung[-14,]
lung$sex <- ifelse(lung$sex==2, 1, 0)
lung$ph.ecog[lung$ph.ecog==3]<-2
t1 <- lung$time
start1 <- c(0.03,0.05,-1,0.7,2,-0.1)
formula1 <- ~lung$sex+factor(lung$ph.ecog)+lung$age
censur1 <- ifelse(lung$status==1,0,1)
fit.model1 <- mle2.GTDL(t = t1,start = start1,
                     formula = formula1,
                     censur = censur1)
fit.model1

### Example 2

data(tumor)
t2 <- tumor$time
start2 <- c(1,-0.05,1.7)
formula2 <- ~tumor$group
censur2 <- tumor$censured
fit.model2 <- mle2.GTDL(t = t2,start = start2,
                       formula = formula2,
                       censur = censur2)
fit.model2