Estimates covariance matrix of the four parameters of normal-polynomial quantile mixture
covnormpoly4(data)
vector of observations
covariance matrix of the four parameters of normal-polynomial quantile mixture
Karvanen, J. 2006. Estimation of quantile mixtures via L-moments and trimmed L-moments, Computational Statistics & Data Analysis 51, (2), 947--959. http://www.bsp.brain.riken.jp/publications/2006/karvanen_quantile_mixtures.pdf.
Lmomcov
for covariance matrix of L-moments,
dnormpoly
for the normal-polynomial quantile mixture and
data2normpoly4
for the estimation of the normal-polynomial quantile mixture.