**Class: **RegressionTree

Regression error by cross validation

`E = cvloss(tree)`

[E,SE] =
cvloss(tree)

[E,SE,Nleaf]
= cvloss(tree)

[E,SE,Nleaf,BestLevel]
= cvloss(tree)

[E,...] = cvloss(tree,Name,Value)

returns
the cross-validated regression error (loss) for `E`

= cvloss(`tree`

)`tree`

,
a regression tree.

`[`

returns the standard
error of `E`

,`SE`

] =
cvloss(`tree`

)`E`

.

`[`

returns the number
of leaves (terminal nodes) in `E`

,`SE`

,`Nleaf`

]
= cvloss(`tree`

)`tree`

.

`[`

returns the optimal
pruning level for `E`

,`SE`

,`Nleaf`

,`BestLevel`

]
= cvloss(`tree`

)`tree`

.

`[`

cross
validates with additional options specified by one or more `E`

,...] = cvloss(`tree`

,`Name,Value`

)`Name,Value`

pair
arguments. You can specify several name-value pair arguments in any
order as `Name1,Value1,…,NameN,ValueN`

.