The pooled estimated standard deviation is obtained by adding together
the residual sum of squares for each non-null element of
object, dividing by the sum of the corresponding residual
degrees-of-freedom, and taking the square-root.
Usage
pooledSD(object)
Arguments
object
an object inheriting from class lmList.
Value
the pooled standard deviation for the non-null elements of
object, with an attribute df with the number of
degrees-of-freedom used in the estimation.