We examine the mechanism by which feature selection improves the accuracy of supervised learning. An empirical bias/variance analysis as feature selection progresses indicates that the most accurate feature set corresponds to the best bias-variance trade-off point for the learning algorithm. Often, this is not the point separating relevant from irrelevant features, but where increasing variance...

CONTEXT Factors that interfere with the ability to interpret assessment scores or ratings in the proposed manner threaten validity. To be interpreted in a meaningful manner, all assessments in medical education require sound, scientific evidence of validity. PURPOSE The purpose of this essay is to discuss 2 major threats to validity: construct under-representation (CU) and construct-irrelevan...

The purpose of this research was to study the effects of violations of standard multiple-choice item writing principles on test characteristics, student scores, and pass-fail outcomes. Four basic science examinations, administered to year-one and year-two medical students, were randomly selected for study. Test items were classified as either standard or flawed by three independent raters, blin...

This study examined the substantive and predictive validity facets of the University Entrance Examination for English Major (UEEEM) students. To that aim, 111 English major students were recruited to report their scores on each of the subtests of the test as well as their grade point average. Sequential multiple regressions and factor analysis were used in the analysis of the data. Results ackn...

The relations among age, inhibition, perceptual speed, susceptibility to interference, and working memory were examined in a sample of 301 adults age 20 to 90. Younger adults were found to have more efficient inhibitory mechanisms than were older adults. Significant inhibition, however, was found in all age groups, including the older age group. Older adults were also found to be more susceptib...

In a recent project the Ada language turned out to be not as flexible as we expected it to be. This forced us to model our application in a way that was less elegant, less maintainable and less efficient. In this paper we propose to add a language construct to the language that would enable us to do what we were missing. The extension is based on finite unions with dispatching and can quite eas...

A hyperbolic bration is set of q ?1 hyperbolic quadrics and two lines which together partition the points of PG(3; q). The classical example of a hyperbolic bration comes from a pencil of quadrics; however, several other families are known. In this paper we construct a new family of hyperbolic brations for odd prime powers q. As an application of hyperbolic brations, we note that they can be us...

this study examined the substantive and predictive validity facets of the university entrance examination for english major (ueeem) students. to that aim, 111 english major students were recruited to report their scores on each of the subtests of the test as well as their grade point average. sequential multiple regressions and factor analysis were used in the analysis of the data. results ackn...

This paper points out a conceptual difficulty in using a variance decomposition to assess the quantitative importance of news shocks. A variance decomposition will attribute to news shocks movements in endogenous variables driven both by news about future exogenous fundamentals that has yet to materialize (what I call “pure news”) as well as movements driven by realized changes in fundamentals ...