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brainGraph (version 2.0.2)

brainGraph_GLM_design: Create a design matrix for linear model analysis

Description

brainGraph_GLM_design takes a data.table of covariates and returns a design matrix to be used in linear model analysis.

Usage

brainGraph_GLM_design(covars, coding = c("dummy", "effects", "cell.means"),
  mean.center = FALSE, binarize = NULL, int = NULL)

Arguments

covars

A data.table of covariates

coding

Character string indicating how factor variables will be coded (default: 'dummy')

mean.center

Logical indicating whether to mean center non-factor variables (default: FALSE)

binarize

Character string specifying the column name(s) of the covariate(s) to be converted from type factor to numeric (default: NULL)

int

Character string specifying the column name(s) of the covariate(s) to test for an interaction (default: NULL)

Value

A numeric matrix

Details

There are three different ways to code factors: dummy, effects, or cell-means (chosen by the argument coding). To understand the difference, see Chapter 7 of the User Guide.

The argument mean.center will mean-center (i.e., subtract the mean of the entire dataset from each variable) any non-factor variables (including any dummy/indicator covariates). binarize will convert the given factor variable(s) into numeric variable(s), which is performed before mean-centering.

int specifies which variables should interact with one another. This argument accepts both numeric (e.g., Age) and factor variables (e.g., Sex). All interaction combinations will be generated: if you supply 3 variables, all two-way and the single three-way interaction will be generated. This variable must have at least two elements.

See Also

Other GLM functions: GLMfit, brainGraph_GLM, mtpc