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Biomedical subjects

G E Stone

Publications and source records attributed to G E Stone.

8 recordsLinked to original sources

Objective standard setting (or truth in advertising).

Over the past 40 years criterion referencing has become the major method for setting passing standards on most high-stakes examinations. This paper serves three purposes. First it reveals the limitations and methodological weaknesses of most popular standard setting models, supported by a large volume of prior investigation. Second, it presents a radically different approach to the question of setting standards. The new model called Objective Standard Setting was developed in the early 1990s and has been successfully practiced in a variety of settings since that time. While presented in educational forums for many years, this paper represents the first published account of its methods. Thirdly,suggestions for new considerations of validity in standard setting are addressed. There port concludes with the suggestion that however well-intentioned popular standard setting efforts may be, psychometric experts must more carefully and fully understand the models behind their practices and the validity, meaning and implications of their thought processes.

Confidence Intervals↗

Synchronized cell division in Tetrahymena pyriformis following inhibition with vinblastine.

The ability of Tetrahymena pyriformis to undergo synchronous division following release of inhibition with vinblastine was examined. The degree of synchrony was shown to be correlated with the period of time spent under the influence of vinblastine. Cells were inhibited for different periods of time with vinblastine and then washed free of the inhibitor with fresh medium. The increase in cell number and division index was followed subsequent to release of inhibition. Inhibition for a period of time equal to about two generation times was required to produce a complete doubling of the population during the first division. Inhibition for longer periods of time resulted in the population's increasing by more than a factor of two during the first division burst. The nuclear cytology indicates that the micronucleus is probably blocked in mitosis.

Animals↗