ABSTRACT
We have already seen [Eq. (4-5) or (4-9)] that true-score ζ or ξ on a test is simply a monotonic transformation of ability θ. The transformation is different from test to test. If we know the distribution g(ζ) of true score, the joint distribution of true score and observed score is https://www.w3.org/1998/Math/MathML"> ϕ ( x , ζ ) = g ( ζ ) h ( x | ζ ) , https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780203056615/d669de6a-43de-4879-97fb-c978825c4fe9/content/math_345_B.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/>
