Studies of reaction-time distributions provide a useful quantitative approach to understand decision processes at the neural level and at the behavioral level. A strong relationship between the spread of latencies and the median is generally accepted even though there has been no attempt to disentangle experimentally these two parameters. Here we test the ability to independently control the me...

The purpose of this review is to clarify the concepts of bias, precision and accuracy as they are commonly defined in the biostatistical literature, with our focus on the use of these concepts in quantitatively testing the performance of point estimators (specifically species richness estimators). We first describe the general concepts underlying bias, precision and accuracy, and then describe ...

Digital subtraction radiography requires close matching of the contrast in the films to be subtracted. A digital melhod is presented permitting the retrospective correction of film contrast differences. The method is nonparanietric and derives the required gray level transformation directly from the histograms associated with the radiographs. This transform is shown to be unique and monotonic. ...

PURPOSE This study examined the use of the Tucker linear equating method in producing an individual student's score in 3 groups with bridging stations over 3 consecutive days of the clinical performance examination (CPX) and compared the differences in scoring patterns by bridging number. METHODS Data were drawn from 88 examinees from 3 different CPX groups-DAY1, DAY2, and DAY3-each of which ...

A novel approach to quantifying postural stability in single leg stance is assessment of time-to-boundary (TTB) of center of pressure (COP) excursions. TTB measures estimate the time required for the COP to reach the boundary of the base of support if it were to continue on its instantaneous trajectory and velocity, thus quantifying the spatiotemporal characteristics of postural control. Our pu...

In Table 4, the values for mean and standard deviation are incorrect. Please see the corrected Table 4 here.

Hungry, unrestrained rats (N = 7) were rewarded for pressing a response beam in excess of 11 different force requirements. Changes in peak force production as a function of peak force requirement were examined by analyses of the first four moments of distributions of peak response forces: constant error, the within-subject standard deviation, skewness, and kurtosis. Results were similar to thos...

A new approach for predicting a wide range of physical and thermodynamic properties is proposed. It involves calculation of the molecular descriptors of a target compound of unknown properties, followed by regression of this vector of molecular descriptors versus a database of compounds with known descriptors and measured properties. The regression model, obtained for the descriptors of a targe...

OBJECTIVES Few studies have explicitly tested whether the health disadvantage among older blacks is consistent across the entire range of education. We examined racial differences in the cross-sectional association of education with physical and cognitive function performance in older adults. METHODS Participants included over 9500 blacks and whites, aged ≥ 65 years, from the Chicago Health a...