contr_code_sum: Sum code a factor

In faux: Simulation for Factorial Designs

Sum code a factor

Description

Sum coding sets the grand mean as the intercept. Each contrast compares one level with the grand mean.

Usage

contr_code_sum(fct, levels = NULL, omit = length(levels), colnames = NULL)

Arguments

fct	the factor to contrast code (or a vector)
levels	the levels of the factor in order
omit	the level to omit (defaults to the last level)
colnames	optional list of column names for the added contrasts

Value

the factor with contrasts set

Examples

df <- sim_design(between = list(pet = c("cat", "dog", "bird", "ferret")), 
                 mu = c(2, 4, 9, 13), empirical = TRUE, plot = FALSE)

df$pet <- contr_code_sum(df$pet)
lm(y ~ pet, df) %>% broom::tidy()

df$pet <- contr_code_sum(df$pet, omit = "cat")
lm(y ~ pet, df) %>% broom::tidy()

df$pet <- contr_code_sum(df$pet, omit = 1)
lm(y ~ pet, df) %>% broom::tidy()

faux documentation built on April 3, 2025, 7:44 p.m.