Regression error

returns the mean squared error between the predictions of `L`

= loss(`tree`

,`tbl`

,`ResponseVarName`

)`tree`

to the data in `tbl`

, compared to the true responses
`tbl.ResponseVarName`

.

computes the error in prediction with additional options specified by one or more
`L`

= loss(___,`Name,Value`

)`Name,Value`

pair arguments, using any of the previous
syntaxes.