nullModel {caret} | R Documentation |
Fit a single mean or largest class model
nullModel(x, ...) ## Default S3 method: nullModel(x = NULL, y, ...) ## S3 method for class 'nullModel': predict(object, newdata = NULL, ...)
x |
An optional matrix or data frame of predictors. These values are not used in the model fit |
y |
A numeric vector (for regression) or factor (for classification) of outcomes |
... |
Optional arguments (not yet used) |
object |
An object of class nullModel
|
newdata |
A matrix or data frame of predictors (only used to determine the number of predictions to return) |
nullModel
emulates other model building functions, but returns the simplest model possible given a training set: a single mean for numeric outcomes and the most prevalent class for factor outcomes.
The output of nullModel
is a list of class nullModel
with elements
call |
the function call |
value |
the mean of y or the most prevalent class |
levels |
when y is a factor, a vector of levels. NULL otherwise |
n |
the number of elements in y |
predict.nullModel
returns a either a factor or numeric vector depending on the class of y
. All predictions are always the same.
outcome <- factor( sample(letters[1:2], size = 100, prob = c(.1, .9), replace = TRUE)) useless <- nullModel(y = outcome) useless predict(useless, matrix(NA, nrow = 10))