The paper gives some basic ideas of both the construction and investigation of the properties of the Bayesian estimates of certain parametric functions of the parent exponential distribution under the model of random censorship assuming the Koziol-Green model. Various prior distributions are investigated and the corresponding estimates are derived. The stress is put on the asymptotic properties of the estimates with the particular stress on the Bayesian risk. Small sample properties are studied via simulations in the special case.
Transportation system safety and reliability pertain to the dominant factors affecting present life of human society. In this paper, we describe the method for an analysis and further subsequent optimization of complex transportation system safety and reliability based on their complex sensitivity investigation. Reasonable applications of this theoretical tool can also be used for improvement of complex transportation system resistance against terrorist activities.
Objectives. The aim of the present study was to adapt the English self-report questionnaire Toronto Alexithymia Scale-20 (TAS-20) to Slovak conditions, as well as to evaluate its reliability and to investigate its 3-factor structure reported by the authors. TAS-20 is used to measure the construct of alexithymia and its 3 components identified by the authors (i.e. difficulty identifying feelings, difficulty describing feelings and externally-oriented thinking). Subjects and setting. After having done a back- translation in cooperation with the author of I AS-20, its reliability and factor validity was evaluated within the sample of 242 university female students. Statistical analysis. The structure of TAS-20 c|uestionnaire was examined via confirmatory factor analysis (maximum likelihood procedure). Cronbach coefficients alpha were calculated to assess internal consistency aspect of reliability of the TAS-20 scale and its subscales. Results. It has been shown that TAS-20 represents a reliable measurement instrument. Although the results of CFA supported the 3-factor structure of the Slovak version of TAS-20 they indicated the appropriateness/ plausibility of its alternative 4-factor solution as well. Study limitation, (a) measurement of alexithymia is self-reported; (b) the findings are limited to a sample of university female students., Veronika Látalová, Ľubor Pilárik., and Obsahuje seznam literatury
The definition of the performance parameters, especially accuracy, reliability, dependability are presented. Their estimations are developed by using results from the theory of statistical tolerance intervals in the case of random sample from a normal distribution. The proposed approach is illustrated on two examples.
Súčasný vývoj v oblasti psychologického hodnotenia zdôrazňuje zlepšovanie metodológie a význam zvyšovania efektívnosti. Algoritmy počítačového adaptívneho testovania (CAT) založené na teórii odpovede na položku (IRT) ponúkajú zaujímavé príležitosti pre súčasnú optimalizáciu ako presnosti, tak aj efektívnosti merania. Tento článok prezentuje zistenia 15 výskumných štúdií z oblasti testovania schopností, klinickej psychológie, testovania osobnosti a zdravotníckej starostlivosti zameraných na skúmanie reliability, užitočnosti (v zmysle úspory položiek) a validity (v zmysle korelácií s existujúcimi nástrojmi) CAT. Celkovo sú zistenia povzbudivé – CAT poskytuje efektívny prostriedok pre získanie optimálneho množstva informácie potrebnej pre zodpovedanie posudzovanej otázky, a to využitím minimálneho množstva času a/alebo počtu položiek pre získanie danej informácie. CAT skóre silno korelovalo so skóre z celej položkovej banky (rozpätie r = 0,83 – 0,99) a stredne silno so zaužívanými nástrojmi (rozpätie r = 0,58 – 0,83) poskytujúc dôkazy pre reliabilitu, validitu a porovnateľnosť adaptívnych nástrojov. Avšak tieto výsledky sú založené hlavne na CAT simulačných štúdiách a preto sú potrebné ďalšie štúdie zahŕňajúce administráciu skutočných testov živým respondentom, aby tieto zistenia potvrdili. and Computerized adaptive testing: precision, validity and efficiency
Present developments in the area of psychological assessment place emphasis on methodological improvements and the importance of increasing effectiveness. Computerized adaptive testing (CAT) algorithms based on item response theory (IRT) offer attractive opportunities for simultaneously optimizing both measurement precision and efficiency. This article presents findings of 15 research studies from field of ability testing, clinical psychology, personality testing and health care designed to explore the reliability, utility (in terms of item savings) and validity (in terms of correlations with existing tools) of CAT. Overall, the findings are encouraging – CAT provides an efective means to gain an optimal amount of information needed to answer an assessment question, while keeping time and/or number of items required to obtain that information at a minimum. CAT score correlated high with score from the full item bank (range r = 0,83 – 0,99) and moderately with established measures (range r = 0,58 – 0,83) provide the evidence for reliability, validity and comparability of adaptive tools. However, these results are based mainly on CAT simulation studies and therefore additional Live-CAT studies (involves the administration of real tests to live examinees) are needed to confirm this pattern of findings.
Problematice stresu je věnována značná pozornost. Proto je třeba mít k dispozici jednoduchý a přitom spolehlivý nástroj umožňující stanovit aktuální hladinu stresu. Cílem tohoto příspěvku je představit prvotní psychometrické ověření české verze Škály vnímaného stresu vyvinuté původně Cohenem v roce 1983, která je v tomto směru jednou z nejčastěji užívaných metod. Ověření dotazníku obsahujícího 10 položek bylo realizováno na vzorku zahrnujícím 358 respondentů z řad studentů vysokých škol. Statistické zpracování zahrnovalo mimo jiné i stanovení vnitřní konzistence dotazníku a konfirmační faktorovou analýzu. Česká verze dotazníku vykazovala vysokou míru vnitřní konzistence, když Cronbachovo alfa bylo 0,871. Konfirmační faktorová analýza potvrdila v literatuře preferovanou dvoufaktorovou strukturu dotazníku a ukázala, že uvedený model dosahuje vyhovujících výsledků v absolutních i relativních indexech shody modelu s daty stejně jako v indexech vystihujících úspornost modelu. Česká verze Škály vnímaného stresu je tak reliabilním a validním nástrojem umožňujícím měření aktuální hladiny vnímaného stresu. and Recently, a great attention has been devoted to stress. Thus, it is worth to have a simple and reliable tool measuring the current level of perceived stress. The aim of this paper is to present a validation of the Czech version of the Perceived Stress Scale which was developed by Cohen in 1983 and is a widely used instrument in this field. Verification of the questionnaire containing 10 items was carried out on a group of 358 university students. The statistical analysis included besides other things determination of the internal consistency and confirmatory factor analysis. The Czech version exhibited a high level of internal consistency with Cronbach´s alpha of 0.871. Confirmatory factor analysis revealed a two-factor structure preferred also in the literature and showed adequate values of both absolute and relative fit indices as well as indices of parsimony. The Czech version of the Perceived Stress Scale is valid and reliable instrument enabling measurement of perceived stress.
The motivation of students toward learning is the important part of educational process. Main aim of the study is to realize psychometric validation of the Slovak version AMS – HS28 (Academic Motivation Scale – High School version) questionnaire, which was developed by Vallerand et al. (1992). This research tool contained seven scales, three of them were focused on intrinsic motivation, three of them on extrinsic motivation and one was focused on amotivation. The sample size was created by 201 high school students. The statistical analysis included the determination of internal consistency of questionnaire through Cronbach’s alpha coefficient and also confirmatory factor analysis. Confirmatory factor analysis revealed a seven-factor theoretical model and values of alpha coefficient showed on the internal consistency of whole questionnaire and also of all factors. and Motivácia žiakov k učeniu je významnou súčasťou edukačného procesu. Hlavným cieľom štúdie je realizovať psychometrické overenie slovenskej verzie dotazníku AMS – HS28 (Academic Motivation Scale – High School version), ktorá bola navrhnutá autormi Vallerand et al. (1992). Výskumný nástroj obsahoval sedem škál, tri boli zamerané na vonkajšiu motiváciu, tri na vnútornú a jedna na amotiváciu. Výskumného šetrenia sa zúčastnilo 201 žiakov stredných škôl. Štatistické spracovanie zahrňovalo stanovenie vnútornej konzistencie dotazníka prostredníctvom koeficientu Cronbachovo alfa, a ďalej konfirmačnú faktorovú analýzu. Konfirmačná faktorová analýza potvrdila sedemfaktorový teoretický model a hodnoty koeficientu alfa poukázali na vnútornú konzistenciu tak celého dotazníka, ako aj jednotlivých faktorov.
Zisťovanie kvality života pomocou tradičných kvantitatívnych nástrojov spočíva v predložení zoznamu položiek a vychádza sa z predpokladu, že pokrývajú väčšinu dôležitých aspektov kvality života všetkých osôb a zároveň, že položky majú pre každú osobu rovnakú dôležitosť. Individualizované nástroje naopak predpokladajú, že rôzne aspekty života majú pre rôzne osoby odlišnú dôležitosť a zahŕňajú iba oblasti, ktoré sú pre kvalitu života osoby subjektívne významné. V príspevku sú analyzované psychometrické vlastnosti reprezentantov obidvoch prístupov: dotazník WHOQOL-BREF a GPGI boli porovnávané z hľadiska reliability a validity na vzorke 86 adolescentiek. Na základe získaných výsledkov možno konštatovať: a) povaha celkového skóre individualizovaného nástroja (GPGI) nedovoľuje hodnotiť jeho reliabilitu prostredníctvom koeficienta konzistencie, testretestová reliabilita je rovnaká ako v prípade tradičného nástroja, b) stredne vysoké korelácie GPGI so škálami WHOQOL-BREF poukazujú na to, že obidva nástroje nemerajú identické aspekty kvality života, c) korelácie individualizovaného nástroja s jednopoložkovými škálami subjektívnej pohody sú porovnateľne vysoké so škálou prežívanie, zatiaľ čo ostatné tri škály WHOQOL-BREF s nimi nekorelujú, resp. korelujú nízko, čo poukazuje na fakt, že GPGI korešponduje so subjektívnou pohodou, zo štyroch škál WHOQOL-BREF iba jedna, d) skóre GPGI nediferencovalo medzi chorými a zdravými osobami, avšak škála fyzické zdravie z WHOQOL- BREF je na aktuálne fyzické rozpoloženie opytovaných osôb senzibilná. Diskutované sú nepotvrdené očakávané prednosti individualizovaného nástroja a spôsob získavania jeho celkového skóre., Objectives. Detection of quality of life by means of traditional quantitative measures lies in presenting a list of items and is based on the assumption that they cover majority of important aspects of quality of life for all persons, and that the items are of identical significance for each person. In contrast, individualised measures presuppose that different aspects of life are of different importance for different persons, and include only areas which are subjectively significant for a person´s quality of life. Sample and setting. The paper analyses psychometric qualities of representatives of both approaches: the WHOQOL-BREF and GPGI questionnaires were compared from the viewpoint of their reliability and validity on the sample of 86 adolescent females. Results and limitations. On the basis of the acquired results it is possible to state that a) the nature of the overall score of the individualised instrument (GPGI) does not make it possible to assess its reliability by means of consistency coefficient, test-retest reliability is identical with that of traditional instrument, b) medium scale correlations GPGI with WHOQOL-BREF scales demonstrate that both instruments do not measure identical aspects of quality of life, c) correlations of the individualised measure with single-item scales of subjective well-being are comparable with the domain psychological, while the other three WHOQOL-BREF scales do not correlate with them, or exhibit low correlations, which points to the fact that GPGI corresponds with subjective well-being, of four WHOQOL-BREF scales only one, psychological, d) GPGI score does not differentiate between sick and healthy persons, although the physical health WHOQOL-BREF scale is sensitive to the current physical state of the questioned persons. It is discussed the unconfirmed advantages of the individualised measure and the method of acquisition of its overall score., Jozef Džuka., and Obsahuje seznam literatury
This paper deals with the reliability of composite measurement consisting of true-false items obeying the Rasch model. A definition of reliability in the Rasch model is proposed and the connection to the classical definition of reliability is shown. As a modification of the classical estimator \textit{Cronbach's alpha}, a new estimator \textit{logistic alpha} is proposed. Finally, the properties of the new estimator are studied via simulations in the Rasch model.
This paper deals with a new approach to designing the micro-electronic system suitable for mass-parallel and neuronal structures realizations in which the high demand on safety and reliability is given. The presented concept is based on the FPGA platform. Authors point out various kinds of faults which can possibly occur during system cycle. Furthermore, authors introduce the Safety Core principle and define systems for which it is applicable. There are possibilities of using partial dynamic reconfiguration shown in this paper in the context of FPGA fabric testing, faults catching and correcting.