Construct a sum-to-zero contrast between two logical expressions.
Arguments
- A
A formula representing the first logical expression in the contrast.
- B
A formula representing the second logical expression in the contrast.
- name
A character string specifying the name of the contrast (mandatory).
- where
An optional formula specifying the subset over which the contrast is computed.
Value
A pair_contrast_spec object containing the sum-to-zero contrast between the two logical expressions.
Examples
# A hypothetical experiment with a factor 'category' that takes on values of 'face' and 'scene'
pair_contrast(~ category == "face", ~ category == "scene", name="face_scene")
#> $A
#> ~category == "face"
#> <environment: 0x7f8f62ace760>
#>
#> $B
#> ~category == "scene"
#> <environment: 0x7f8f62ace760>
#>
#> $where
#> NULL
#>
#> $name
#> [1] "face_scene"
#>
#> attr(,"class")
#> [1] "pair_contrast_spec" "contrast_spec" "list"