jackGroupSE {drcSeedGerm}

Delete-a-Petri-dish jackknife

Description

This function estimates standard errors for regression model parameters by using the fully-iterated delete-a-group jackknife (Yu and Peng, 2008). This is asymptotically equivalent to the cluster-robust 'sandwich' variance estimator (Lipsiz, 1994).

Usage

jackGroupSE(obj, data, units)

Arguments

obj

a fitted model object

data

dataset containing the variables used in obj

units

a vector containing the code for Petri dishes

Details

Care should be taken to ensure that the assumptions for using a fully-iterated jackknife are valid.

Value

This function returns a data.frame containing the estimated parameters, the SEs and the robust SEs

Author(s)

Andrea Onofri

References

Yu, B., Peng, Y., 2008. Mixture cure models for multivariate survival data. Computational Statistics and Data Analysis 52, 1524–1532. Lipsitz, S.R., Dear, K.B.G., Zhao, L., 1994. Jackknife Estimators of Variance for Parameter Estimates from Estimating Equations with Applications to Clustered Survival Data. Biometrics 50, 842–846.

Examples

data(rape)

modHTE <- drmte( nSeeds ~ timeBef + timeAf + Psi,
               data=rape, fct=HTE1())
robust <- jackGroupSE(modHTE, rape, rape$Dish)
robust