QuadraticEstimatingEquations/R/a.Crowder.Mod.R
2014-02-23 21:05:36 -05:00

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# First weighting vector of the modified quadratic estimating equation (Crowder)
#
# Author: Francois Pelletier
#
# LGPL-3.0
###############################################################################
#' First weighting vector of the modified quadratic estimating equation (Crowder)
#'
#' @param param Vector of parameters of the distribution function
#' @param Y Individual data sample
#' @param variancef Variance function of the distribution
#' @param dmean Derivative in respect to the parameter vector of the mean function of the distribution
#' @param dsd Derivative in respect to the parameter vector of the standard deviation function of the distribution
#' @return First weighting vector
#'
#' @author Francois Pelletier
a.Crowder.Mod <- function(param,Y,variancef,dmean,dsd)
{
(-(moments::kurtosis(Y)-1)*dmean(param)+
2*moments::skewness(Y)*dsd(param))/
(variancef(param)*gammaf.Crowder.Mod(Y))
}