An upper-asymptote parameter was added to the three-parameter logistic item response model. This four-parameter model was compared to the three-parameter model on four data sets. The fourth parameter increased the likelihood in only two of the four sets. Ability estimates for the students were generally unchanged by the introduction of the fourth…

The primary objective of this paper is to describe a method of estimating female-male wage ratios. The estimating technique presented is two stage least squares (2SLS), in which equations are estimated for both men and women. After specifying and estimating the wage equations, the male-female wage differential is calculated that would remain if…

A technique using information and decision-making theories to evaluate problem solving tactics is presented. In problem solving, the process of solution is evaluated by investigating the questions that the subject doing the problem solving asks. The sequence of questions asked is called a tactic. It is assumed that: (1) tactics are the observable…

This paper discusses the basic theory underlying confidence limits and presents reasons why psychologists should incorporate confidence ranges in their psychodiagnostic reports. Four methods for establishing confidence limits are compared. Three of the methods involve estimated true scores, and the fourth is the standard error of measurement…

Proposes a new definition of the nuclear zone of a Bradford or Leimkuhler curve. The mathematical rationale is outlined, and examples of the application of this technique to citation analysis are given. (15 references) (CLB)

Investigates the properties of a global model consisting of "n" local information retrieval systems based on thesaurus. Definitions of a distributed information retrieval system (thesaurus, documents set, set of queries) and proofs of theorems denoting further properties of the systems are highlighted. Five references are included. (EJS)

The density and Monte Carlo methods for approximating the area under a curve, without relying on calculus, are given. A computer program is included. (MNS)

Describes an intuitive and discovery-oriented approach that can be used to develop formulas for rectangles, triangles, parallelograms, and trapezoids. The approach emphasizes the interrelationships between the formulas. (JN)

The Welch-James procedure may be used to test hypothesis on means, when independent samples from populations with heterogenous variances are available. Summation formulas for the Welch-James procedure are presented for the 2x2 design. Matrix formulas that permit routine application of the procedure to crossed factorial designs are presented.…

The debate over whether and how TIAA-CREF should provide equal periodic retirement benefits to men and women despite different life expectancies is discussed, along with the status of court litigation and company action. (MSE)

Projections for school districts in Maine used a modified cohort survival projection technique. The technique's major factors are past district enrollment and live birth statistics. Projected enrollments are compared with actual enrollments using Pearson product-moment correlations and percentages of error. This provides accurate projections and…

Forty-eight participants read one of three texts (high explanatory, low explanatory, and standard) that varied in the degree of explanation of basic concepts of elementary probability. Performance test data showed that participants in the high-explanatory test condition did equally well on both formula and story problems. (Author/LC)

Estimates of the validity of random short forms can serve as benchmarks against which to appraise the validity of particular short forms. Formulas are presented for estimating the validity of random short forms and illustrated with Wechsler Adult Intelligence Scale-Revised (WAIS-R) and Minnesota Multiphasic Personality Inventory data. (Author/CM)

Results show that the proposed sampling distribution of the test appears to be appropriate only for sample sizes above 50, and for data where the sample size is 10 times the number of variables. For such cases the power of the test is found to be fairly low. (Author/RL)

When a test is made to separate a group into two distinct subgroups, as well as to provide an estimate of the mean performance of one subgroup (or both of them), such estimates will be biased due to the unreliability of the test. Suggestions for corrective procedures are presented. (RL)