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Fits a univariate random forest model y ~ x with the binomial (values 0 and 1) response y and the numeric, character or factor predictor x using ranger::ranger() and returns the area under the ROC curve between the observed responses and the model predictions (see score_auc()).

Cases are weighted with case_weights() to prevent issues arising from class imbalance.

Supports cross-validation via the arguments arguments cv_training_fraction (numeric between 0 and 1) and cv_iterations (integer between 1 and n) introduced via ellipsis (...). See preference_order() for further details.

Usage

f_binomial_rf(df, ...)

Arguments

df

(required, dataframe) with columns:

  • "x": (numeric, character, factor) predictor.

  • "y" (integer) binomial response with unique values 0 and 1.

...

(optional) Accepts the arguments cv_training_fraction (numeric between 0 and 1) and cv_iterations (integer between 1 and Inf) for cross validation.

Value

numeric or numeric vector: AUC

Examples

data(vi_smol)

df <- data.frame(
  y = vi_smol[["vi_binomial"]],
  x = vi_smol[["swi_max"]]
)

#no cross-validation
f_binomial_rf(df = df)
#> [1] 0.8995467

#cross-validation
f_binomial_rf(
  df = df,
  cv_training_fraction = 0.5,
  cv_iterations = 10
  )
#>  [1] 0.7632825 0.7761184 0.7781599 0.7363415 0.7222196 0.7676069 0.7459511
#>  [8] 0.7651879 0.7656979 0.7516886

#categorical predictor
df <- data.frame(
  y = vi_smol[["vi_binomial"]],
  x = vi_smol[["koppen_zone"]]
)

f_binomial_rf(df = df)
#> [1] 0.9328657