intELtest: The integrated likelihood ratio test

Description Usage Arguments Details Value References See Also Examples

View source: R/intELtest.R

Description

intELtest gives a class of the weighted likelihood ratio statistics:

∑_{t\in U}w(t)\{-2\log R(t)\},

where w(t) is an objective weight function, and R(t) is an empirical likelihood (EL) ratio that compares two survival functions at each time point t in the set of observed uncensored lifetimes, U.

Usage

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intELtest(data, g1 = 1, t1 = 0, t2 = Inf, sided = 2,
  nboot = 1000, wt = "p.event", alpha = 0.05, compo = FALSE,
  seed = 1011, nlimit = 200)

Arguments

data

a data frame/matrix with 3 columns. The first column is the survival time. The second is the censoring indicator. The last is the grouping variable. An example as the input to data provided is hepatitis.

g1

the group with longer survival in one-sided testing with the default value of 1.

t1

pre-specified t_1 based on domain knowledge with the default value of 0

t2

pre-specified t_2 based on domain knowledge with the default value of

sided

2 if two-sided test, and 1 if one-sided test. It assumes the default value of 2.

nboot

number of bootstrap replications in calculating critical values with the defualt value of 1000.

wt

a string for the integral statistic with a specific weight function. There are four types of integral statistics provided: "p.event", "dF", "dt", and "db". It assumes the default value of "p.event". See 'Details' for more about the integral statistics.

alpha

pre-specified significance level of the test with the default value of 0.05

compo

FALSE if taking the standardized square of the difference as the local statisic for two-sided testing, and TRUE if constructing for one-sided testing, but only the positive part of the difference included. It assumes the default value of FALSE.

seed

the parameter with the default value of 1011 to set.seed for generating bootstrap-based critical values in R. The set.seed is used implicitly in intELtest.

nlimit

the splitting unit with the default value of 200. To deal with large data problems, the bootstrap algorithm is to split the number of bootstrap replicates into nsplit parts. The number nsplit is the smallest integer not less than ≤ft\| U\right\|/nlimit.

Details

intELtest calculates the weighted likelihood ratio statistics:

∑_{i=1}^{h}w_i\cdot \{-2\log R(t_i)\},

where w_1,...,w_h are the values of the weight function evaluated at the distinct ordered uncensored times t_1,...,t_h in U. There are four types of weight functions considered.

Value

intELtest returns a list with three elements:

References

See Also

hepatitis, supELtest, ptwiseELtest

Examples

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library(EL2Surv)
intELtest(hepatitis)

## OUTPUT:
## $teststat
## [1] 1.406016
## 
## $critval
## [1] 0.8993514
## 
## $pvalue
## [1] 0.012

EL2Surv documentation built on Aug. 13, 2018, 9:03 a.m.