cnorm.betabinomial2: Fit a beta-binomial regression model for continuous norming

In cNORM: Continuous Norming

Fit a beta-binomial regression model for continuous norming

Description

This function fits a beta-binomial regression model where both the alpha and beta parameters of the beta-binomial distribution are modeled as polynomial functions of the predictor variable (typically age). While 'cnorm-betabinomial' fits a beta-binomial model on the basis of \mu and \sigma, this function fits a beta-binomial model directly on the basis of \gamma and \beta.

Usage

cnorm.betabinomial2(
  age,
  score,
  n = NULL,
  weights = NULL,
  alpha_degree = 3,
  beta_degree = 3,
  control = NULL,
  scale = "T",
  plot = T
)

Arguments

age	A numeric vector of predictor values (e.g., age).
score	A numeric vector of response values.
n	The maximum score (number of trials in the beta-binomial distribution). If NULL, max(score) is used.
weights	A numeric vector of weights for each observation. Default is NULL (equal weights).
alpha_degree	Integer specifying the degree of the polynomial for the alpha model. Default is 3.
beta_degree	Integer specifying the degree of the polynomial for the beta model. Default is 3.
control	A list of control parameters to be passed to the 'optim' function. If NULL, default values are used.
scale	Type of norm scale, either "T" (default), "IQ", "z" or a double vector with the mean and standard deviation.
plot	Logical indicating whether to plot the model. Default is TRUE.

Details

The function standardizes the input variables, fits polynomial models for both the alpha and beta parameters, and uses maximum likelihood estimation to find the optimal parameters. The optimization is performed using the L-BFGS-B method.

Value

A list of class "cnormBetaBinomial2" containing:

alpha_est	Estimated coefficients for the alpha model
beta_est	Estimated coefficients for the beta model
se	Standard errors of the estimated coefficients
alpha_degree	Degree of the polynomial for the alpha model
beta_degree	Degree of the polynomial for the beta model
result	Full result from the optimization procedure

cNORM documentation built on Nov. 4, 2024, 5:07 p.m.