R code for analyzing data from tests and rating scales.

January 9, 2024 A major cleanup of the code was required to solve the issue that the plot of the last item was greatly distorted.

March 15, 2024 A number of bugs fixed.

September 16, 2024 Bspline basis functions will return values of 0 if the order of the spline is equal to the number of basis functions. This is especially helpful for the elementary two-basis case that is the spline basis version of the classic nominal model used by Darrell Bock for modelling multi-option tests and rating scales.