Psychometric methods

Symptoms of this kind escape today s psychometric methods they are not... 

Although the g factor is necessarily revealed by psychometric methods, it is not exclusively a psychometric construct, nor is it a methodological artefact of the way psychometric tests are constructed or of the particular factor-analytic algorithms used to extract g. The extra-psychometric reality of g is indicated by the many significant correlations that g has with a wide variety of variables, both physical and behavioural, that have no intrinsic or conceptual relationship to psychometrics or factor analysis. In this respect, g seems to differ from other psychometric factors (Jensen 1993,1994). 

Psychometric methods. A very common method of measuring the humidity is to determine simultaneously the wet-bulb and dry-bulb temperatures. From these readings the humidity is found by locating the psychrometric line intersecting the saturation line at the observed wet-bulb temperature and following the psychrometric line to its intersection with the ordinate of the observed diy-bulb temperature. 

CS Watson, DG Pelli. Quest A Bayesian adaptive psychometric method. Percept Psychophys 33 113-120, 1983. 

The aim of applying mathematical and statistical methods is first of all to detect and secondly to describe the interrelations between influencing forces on the one hand, and the interrelations between these influences and the resulting effects on the other hand. Subsequently, new scientific subdisciplines such as biometrics, psychometrics, medical statistics, econometrics, etc. have been developed. These developments have been reflected by the publication of corresponding journals, for example Biometrika (1901), Psycho-metrika (1936), Technometrics (1959) [GELADI, 1995]. Chemometrics was, therefore, not the first discipline of its kind. 

PLS is often presented as the major regression technique for multivariate data. In fact its use is not always justified by the data, and the originators of the method were well aware of this, but, that being said, in some applications PLS has been spectacularly successful. In some areas such as QSAR, or even biometrics and psychometrics,... 

Some of the most interesting theoretical developments in chemometrics over the past few years have been in so-called multiway or multimode data analysis. Many such methods have been available for some years, especially in the area of psychometrics, and a few do have relevance to chemistry. It is important, though, not to get too carried away with the excitement of these novel theoretical approaches. We will restrict the discussion here to trilinear PLS1, involving a three-way x block and a single c variable. If there are several known calibrants, the simplest approach is to perform trilinear PLS1 individually on each variable. 

Disorders of cerebral functions on the one hand and of the water and electrolyte balance on the other hand are the earliest and most reliable hints of the onset of decompensation in severe liver disease, especially cirrhosis. In clinical terms, they can be easily diagnosed as latent hepatic encephalopathy (by carrying out psychometric tests) and/or latent oedema (by recording the increase in body weight). For this reason, these examination methods are also of fundamental importance in the follow-up of chronic liver disease, (s. fig. 15.3)... 

The same method of correlated vectors based on the -loadings of many different psychometric tests has revealed the predominant relationship ofg to various non-psychometric variables in studies from different laboratories around the world (all of them referenced in Jensen 1998). Typical vector correlations are shown in parentheses ... 

Kruskal JB, Simple structure for three-way data A new method intermediate between 3-mode factor analysis and PARAFAC-CANDECOMP, paper presented at the 53rd Annual Meeting of the Psychometric Society, Los Angeles, 1988. 

Grandjean P, Beckmann J, Ditlev G Relation between subjective symptoms and psychometric test results, in Neurohehavioral Methods in Occupational Health. Edited by Gilioli R, Cassitto MG, Foa V. Oxford, UK, Pergamon, 1983, pp 301-308... 

L a b color space A method of depicting color that is uniform and recommended by the Comission Internationale d Eclairage for standard color description. L - psychometric lightness (0 = black 100 = white) a psychometric red ( +ve values), green (-ve values) b psychometric yellow (+ve values), blue (-ve values). 

The measurements of performance capacities associated with human functions should conform to certain criteria. Details can be found in Brand and Crownshield [ 1981 ] and Chaffin [ 1982]. A general set of psychometric criteria is also discussed by Sanders and McCormick [1993]. It includes measurement accuracy, reliability, validity, sensitivity, and freedom from contamination. Meeting these criteria depends not only on the instruments used but also on the methods of analysis and the expertise of the analyst. It is almost impossible to satisfy these criteria perfectly, especially when the task is being performed in its natural environment (as opposed to a laboratory simulation). However, the analyst must always be aware of them and must be pragmatic in measuring task variables. Meister [1985] lists the following practical requirements for measurements (1) objective, (2) quantitative, (3) unobtrusive, (4) easy to collect, (5) requiring no special data-coUection techniques or instrumentation, and (6) of relatively low cost in terms of money and effort by the experimenter. However, these are not necessarily mutually exclusive. 

These methods are based on measuring air temperature in equilibrium with a product and some other air characteristic like water content, wet bulb temperature, or dew temperature. With these data and the use of an enthalpy diagram of moist air or tables, its hygrometric level can be measured and thus the value of the product in equilibrium with this air. There are chromatographic, psychometric, and manometric methods. 

Analyses of each instrument s psychometric properties has shown that exploratory factor analysis (EFA) was conducted for two measures and confirmatory factor analysis (CFA) for two measrrres. In the case of 10 measures both methods were ttsed. 

The problem of the difference between objective risk and subjective risk perception is avoided by the so-called psychometric models which aim to directly record subjective evaluations as a basis for decision-making processes. The expressed preference method [9-10], which uses opinion polls, did, however, show the change in the way the population evaluates technical developments. 

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