One-way Contrast

Create a one-way contrast specification

Usage

oneway_contrast(A, name, where = NULL, basis = NULL, basis_weights = NULL)

Arguments

A

A formula specifying the contrast

name

The name of the contrast

where

An optional formula specifying the subset over which the contrast is computed.

basis

NULL (default: use all basis functions), an integer vector specifying which basis function indices to include, or "all". See pair_contrast for details on basis filtering.

basis_weights

NULL (default: equal weights), or a numeric vector of weights to apply to the selected basis functions. Must have one weight per selected basis function (all of them when basis is NULL or "all") and will be normalized to sum to 1. See pair_contrast for details on basis weighting.

Value

A oneway_contrast_spec object that can be used to generate contrast weights

See also

interaction_contrast for testing interactions, pair_contrast for pairwise comparisons

Examples

# Create a one-way contrast for a factor 'basis'
con <- oneway_contrast(~ basis, name = "Main_basis")

# Create a one-way contrast with a 'where' clause
con <- oneway_contrast(~ basis, name = "Main_basis",
                      where = ~ block == 1)

# Test only first two basis functions
con <- oneway_contrast(~ condition, name = "Main_early", basis = 1:2)