asrtests {asreml3Plus}R Documentation

Forms an object of S3-class asrtests that stores a fitted asreml object, a pseudo-anova table for the fixed and a history of changes and hypthesis testing used in obtaining the model.

Description

An object of S3-class asrtests consists of a list containing:

  1. asreml.obj: an asreml object containing the fit of the model;

  2. wald.tab: a data.frame containing a pseudo-anova table for the fixed terms produced by wald.asreml, which will be called if wald.tab is NULL;

  3. test.summary: a data.frame with columns term, DF, denDF, p and action. A row is added to it for each term that is dropped, added or tested or a note that several terms have been added or removed. A row contains the name of the term, the DF, the p-value and the action taken. Possible codes are: Dropped, Retained, Swapped, Unswapped, Significant, Nonsignificant, Absent, Added, Removed and Boundary. If the changed model did not converge, Unconverged will be added to the code. Note that the logical asreml.obj$converge also reflects whether there is convergence.

A call to asrtests with test.summary = NULL re-initializes the test.summary
data.frame.

Usage

asrtests(asreml.obj, wald.tab = NULL, test.summary = NULL, 
                denDF = "default", ...)

Arguments

asreml.obj

an asreml object for a fitted model.

wald.tab

a data.frame containing a pseudo-anova table for the fixed terms produced by wald.asreml; it should have 4 columns. Sometimes wald.asreml returns a data.frame and at other times a list. For example, it may return a list when denDF is used. In this case, the Wald component of the list is to be extracted and stored.

test.summary

a data.frame with columns term, DF, denDF, p and action containing the results of previous hypothesis tests.

denDF

Specifies the enthod to use in computing approximate denominator degrees of freedom when wald.asreml is called. Can be none to suppress the computations, numeric for numerical methods, algebraic for algebraic methods or default, the default, to autommatically choose numeric or algebraic computations depending on problem size. The denominator degrees of freedom are calculated according to Kenward and Roger (1997) for fixed terms in the dense part of the model.

...

further arguments passed to wald.asreml.

Value

An object of S3-class asrtests.

See Also

asreml3Plus-package, testranfix.asrtests, choose.model.asrtests, rmboundary.asrtests,
sig.devn.reparam.asrtests

Examples

## Not run: 
data(Wheat.dat)

# Fit initial model
current.asr <- asreml(yield ~ Rep + WithinColPairs + Variety, 
                      random = ~ Row + Column + units,
                      rcov = ~ ar1(Row):ar1(Column), 
                      data=Wheat.dat)

# Load current fit into an asrtests object
current.asrt <- asrtests(current.asr, NULL, NULL)

# Check for and remove any boundary terms
current.asrt <- rmboundary.asrtests(current.asrt)

## End(Not run)

[Package asreml3Plus version 2.0-14 Index]