lrpPVal {longRPart}R Documentation

Calculate p-values for the longitudinal regression tree

Description

Using permutation tests, this function calculates the p-value for the first split of the tree; see the linked pdf for details. It also calculates the p-value for the entire tree, though the statistical theory behind this p-value is not as clear.

Usage

lrpPVal(model,J)

Arguments

model model produced by longRPart
J number of permutations to run

Details

The basic principle behind the test is to randomized the covariates to the subject and then recalculate the tree: the p-value is the proportion of trees that have a greater reduction in deviance than the original tree.

Note

J indicates that a longRPart tree will be built J times, and a reasonable value for J would be 100 (at least), which should take 100 times as long as the original longRPart function

Author(s)

Mohamed Abdolell <mo@dal.ca> and Sam Stewart

References

Abdolell et al. Binary partitioning for continuous longitudinal data: categorizing a prognostic variable. Statistics in Medicine (2002) vol. 21 pp. 3395-3409

See Also

../doc/permutation.pdf


[Package longRPart version 1.0 Index]