R/dispersion.pooled.R

In mbest: Moment-Based Estimation for Hierarchical Models

# Copyright 2014 Patrick O. Perry
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.


# compute pooled dispersion estimates
dispersion.pooled <- function(dispersion, df.residual)
{
    df.residual.tot <- sum(df.residual)
    dispersion.tot <- if (df.residual.tot > 0)
        sum(df.residual * dispersion) / df.residual.tot
    else mean(dispersion)
    dispersion.tot
}