varcovcub0q function

Variance-covariance matrix of CUB models with covariates for the feeling component

Compute the variance-covariance matrix of parameter estimates of a CUB model with covariates for the feeling component.

varcovcub0q(m, ordinal, W, pai, gama)

Arguments

• m: Number of ordinal categories
• ordinal: Vector of ordinal responses
• W: Matrix of covariates for explaining the feeling component
• pai: Uncertainty parameter
• gama: Vector of parameters for the feeling component, whose length is NCOL(W)+1 to include an intercept term in the model (first entry of gama)

Details

The function checks if the variance-covariance matrix is positive-definite: if not, it returns a warning message and produces a matrix with NA entries.

Examples

data(univer)
m<-7
ordinal<-univer[,9]
pai<-0.86
gama<-c(-1.94, -0.17)
W<-univer[,4]           
varmat<-varcovcub0q(m, ordinal, W, pai, gama)

References

Piccolo D.(2006), Observed Information Matrix for MUB Models. Quaderni di Statistica, 8 , 33--78,