chi2cub2cov function

Pearson $X^2$ statistic for CUB models with one discrete covariate for feeling

Compute the $X^2$ statistic of Pearson for the goodness of fit of a CUB model for ordinal responses, where the feeling parameter is explained via a logistic transform of the only discrete covariate. It groups ratings in classes according to the values of the covariate.

chi2cub2cov(m, ordinal, covar1, covar2, pai, gama)

Arguments

• m: Integer: number of ordinal categories
• ordinal: Vector of ordinal responses
• covar1: Vector of the first covariate values for explaining the feeling component
• covar2: Vector of the second covariate values for explaining the feeling component
• pai: Uncertainty parameter
• gama: Vector of parameters for the feeling component, with length equal to 2 to account for an intercept term (first entry)

Returns

It returns the following results in a list: - df: Number of degrees of freedom

• chi2: Value of the Pearson fitting measure

• dev: Deviance indicator

References

Tutz, G. (2011). Regression for categorical data, Cambridge Series in Statistical and Probabilistic Mathematics