Statistical inference concerning the parameters of k multivariate normal populations is considered. Several models in which the parameters have certain hierarchical relationships are discussed, in particular as related to testing the hypothesis that k psychological tests are parallel forms of the same test. The report contains the following…

This paper proposes a general model for free-response data collected for measuring a specified unidimensional psychological process; systematizes situations which vary with respect to the scoring level of items; and finds out general conditions for the operating characteristic of an item response category to provide a unique maximum likelihood…

We concern ourselves with the hypothesis that two variables have a perfect disattenuated correlation, hence measure the same trait except for errors of measurement. This hypothesis is equivalent to saying, within the adopted model, that true scores of two psychological tests satisfy a linear relation. Statistical tests of this hypothesis are…