ModelMatrix

This model matrix is similar to <code>model.matrix</code>. But it does not omit unnecessary columns.

This is a core implementation of 'SAS' procedures for linear models - GLM, REG, ANOVA, TTEST, FREQ, and UNIVARIATE. Some R packages provide type II and type III SS. However, the results of nested and complex designs are often different from those of 'SAS.' Different results does not necessarily mean incorrectness. However, many wants the same results to SAS. This package aims to achieve that.
Reference: Littell RC, Stroup WW, Freund RJ (2002, ISBN:0-471-22174-0).

Kyun-Seop Bae

sasLM

'SAS' Linear Model

ModelMatrix function

<dl> <dt>Formula</dt>
<dd>a conventional formula for a linear model</dd> <dt>Data</dt>
<dd>a <code>data.frame</code> to be analyzed</dd> <dt>KeepOrder</dt>
<dd>If <code>KeepOrder</code> is <code>TRUE</code>, terms in <code>Formula</code> will be kept. This is for Type I SS.</dd> <dt>XpX</dt>
<dd>If <code>XpX</code> is <code>TRUE</code>, the cross-product of the design matrix (XpX, X'X) will be returned instead of the design matrix (X).</dd></dl>

Arguments

Author

Model Matrix — ModelMatrix

<dl>

 <dt>Formula</dt>
<dd>a conventional formula for a linear model</dd>

 <dt>Data</dt>
<dd>a <code>data.frame</code> to be analyzed</dd>

 <dt>KeepOrder</dt>
<dd>If <code>KeepOrder</code> is <code>TRUE</code>, terms in <code>Formula</code> will be kept. This is for Type I SS.</dd>

 <dt>XpX</dt>
<dd>If <code>XpX</code> is <code>TRUE</code>, the cross-product of the design matrix (XpX, X'X) will be returned instead of the design matrix (X).</dd>

</dl>

ModelMatrix: Model Matrix

Description

Usage

Value

Arguments

Author

Details