Last data update: 2014.03.03
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R: Wald Test for Stratification Factors
wald.strata | R Documentation |
Wald Test for Stratification Factors
Description
It performs a Wald test to test the hypothesis of equal spline coefficients among strata
in the approximation of baseline risk function.
Usage
wald.strata(fit)
Arguments
fit |
an object of class jointModel with method = "spline-PH-GH"
and with a strata specification in the survival part.
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Value
an object of class wald.strata with components:
alternative |
a character string naming the alternative.
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Result |
a numeric matrix with the results of the Wald test.
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Note
This test is valid when the same knots have been used across strata.
Author(s)
Dimitris Rizopoulos d.rizopoulos@erasmusmc.nl
References
Rizopoulos, D. (2012) Joint Models for Longitudinal and Time-to-Event Data: with
Applications in R. Boca Raton: Chapman and Hall/CRC.
Examples
## Not run:
fitLME <- lme(log(serBilir) ~ drug * year - drug, random = ~ year | id,
data = pbc2)
fitSURV <- coxph(Surv(years, status2) ~ drug + strata(hepatomegaly),
data = pbc2.id, x = TRUE)
fit.pbc <- jointModel(fitLME, fitSURV, timeVar = "year", method = "spline-PH-aGH")
wald.strata(fit.pbc)
## End(Not run)
Results
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