Estimate the residual variance of a regression model on a given task. If a regression learner is provided instead of a model, the model is trained (see train) first.

estimateResidualVariance(x, task, data, target)

## Arguments

x (Learner or WrappedModel) Learner or wrapped model. (RegrTask) Regression task. If missing, data and target must be supplied. (data.frame) A data frame containing the features and target variable. If missing, task must be supplied. (character(1)) Name of the target variable. If missing, task must be supplied.