Useful Functions for Ridit Analysis
Description
Functions to compute ridit scores of vectors, compute mean ridits
and their standard errors for vectors compared to a reference vector,
as described in Fleiss (1981, ISBN:0-471-06428-9), and compute
means/SEs for multiple groups in matrices. Data can be either
counts or proportions. Emphasis is on ridit analysis of ordered categorical
data such as Likert items and pain-rating scales.