contr_code_treatment: Treatment code a factor

In faux: Simulation for Factorial Designs

Treatment code a factor

Description

Treatment coding sets the mean of the reference level (base) as the intercept. Each contrast compares one level with the reference level.

Usage

contr_code_treatment(fct, levels = NULL, base = 1, colnames = NULL)

Arguments

fct	the factor to contrast code (or a vector)
levels	the levels of the factor in order
base	the index of the level to use as baseline
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")), 
                 mu = c(10, 20), plot = FALSE)
df$pet <- contr_code_treatment(df$pet)
lm(y ~ pet, df) %>% broom::tidy()

df <- sim_design(between = list(pet = c("cat", "dog", "ferret")), 
                 mu = c(2, 4, 9), empirical = TRUE, plot = FALSE)
                 
df$pet <- contr_code_treatment(df$pet)
lm(y ~ pet, df) %>% broom::tidy()

df$pet <- contr_code_treatment(df$pet, base = 2)
lm(y ~ pet, df) %>% broom::tidy()

df$pet <- contr_code_treatment(df$pet, base = "ferret")
lm(y ~ pet, df) %>% broom::tidy()

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