摘要:

A model of the proportions of the population at various stages of cognitive development as a function of age is proposed. It is shown that a number of weaknesses in an earlier model proposed by‐Eckstein&Shemesh (1992a) are avoided. The new model accounts well for empirical data for the age range 13–18 years. The uses of such models in research are discus

ISSN:0007-1102    

DOI:10.1111/j.2044-8317.1995.tb01045.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

ISSN:0007-1102    

DOI:10.1111/j.2044-8317.1995.tb01046.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Suppose thatQis a set of problems and S is a set of skills. Askill functionassigns to each problemqi.e. to each element of Q — those sets of skills which are minimally sufficient to solveq;aproblem functionassigns to each setXof skills the set of problems which can be solved with these skills (aknowledge state). We explore the natural properties of such functions and show that these concepts are basically the same. Furthermore, we show that for every familyKof subsets ofQwhich includes the empty set andQ, there are a setSof (abstract) skills and a problem function whose range is just K. We also give a bound for the number of skills needed to generate a specific set of knowledge states, and discuss various ways to supply a set of knowledge states with an underlying skill theory. Finally, a procedure is described to determine a skill function using coverings in partial orders which is applied to set A of the Coloured Progressive Matrices test (Raven, 1965

ISSN:0007-1102    

DOI:10.1111/j.2044-8317.1995.tb01047.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

A model of recall order discussed by Robertson (1990) is extended to investigate the simultaneous effects of clustering and presentation order effects in single trial free recall. Further extensions are presented to model recall order within multi‐trial free recall. Two examples are presented to illustrate the types of effects which can be include

ISSN:0007-1102    

DOI:10.1111/j.2044-8317.1995.tb01048.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Zipser's (1986) formulation of the beta model for navigation suffers from two major drawbacks; it requires a minimum of three landmarks, and that each landmark's position relative to the current position be accurately estimated. This paper extends the beta model by demonstrating that it can apply in the two landmark case, and also when one of the two landmarks is too distant for its coordinates to be estimated with any accuracy. This enables the model to meet some of the criteria for a successful account of navigation in the rat and the gerbil.

ISSN:0007-1102    

DOI:10.1111/j.2044-8317.1995.tb01049.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

The paper studies the generalized Procrustes problem with the extension of variable weights. A distinction is made between configurations and configuration classes, depending on the type of data used. The main interest is in configuration classes. Two different types of weighting are introduced: the Huber and Tukey weights. The objective is to use the weights to yield a resistant procedure for the generalized Procrustes problem. An algorithm is described and some attention is paid to the starting values in order to avoid non‐optimal solutions. An example and simulation results are presented which show that the weighted approach outperforms least squares when there are outliers in the dat

ISSN:0007-1102    

DOI:10.1111/j.2044-8317.1995.tb01050.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

While the effect of selection in predictive validity studies has long been recognized and discussed in psychometric studies, little consideration has been given to this problem in the context of latent variable models. In a recent paper, Muthén&Hsu (1993) proposed and compared estimators of predictive validity of a multifactorial test. Both selectivity and measurement error were considered in the estimation of predictive validity. The purpose of the present paper is to expand on Muthén&Hsu (1993) by examining and comparing the sampling behaviour of three estimators for predictive validity, LQL (listwise, quasi‐likelihood estimator), FQL (full, quasi‐likelihood estimator) and FS (factor score estimator), using a Monte Carlo approach. Effects of selection procedures, selection ratios and sample sizes on the sampling behaviours of the estimators are also investigated. The results show that FQL and FS are the two preferred estimators and each has different strengths and weaknesses. A real data application is presented to illustrate the practical implementation of the estim

ISSN:0007-1102    

DOI:10.1111/j.2044-8317.1995.tb01051.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

This paper addresses three issues related to the analysis of variance: the practical importance of heteroscedastic methods, replacing means with some other measure of location, with an emphasis on trimmed means, and the problem of how to design meaningful simulation studies. A reasonable argument is that if the variances ofJindependent groups are unequal, surely the means are unequal, in which case there is no worry about a Type I error. Assuming this is true, the temptation is to use the conventionalFtest, but this is a highly undesirable approach for several reasons described in the paper. Another practical concern is whether substantial gains in power can be achieved by switching from means to some other measure of location. It is already known that certain resistant measures of location have substantial advantages over the means when distributions are non‐normal. This paper describes a few new results related to trimmed means. Finally, when simulations are used to study the properties of a particular testing procedure, how should they be designed? In particular, which distributions should be used, and how should our choice be influenced by experience with non‐simulated data from actual studies? Also, which characteristics of a particular testing procedure need to be studied and reported? A few suggestions are made in the hope of improving upon current pract

ISSN:0007-1102    

DOI:10.1111/j.2044-8317.1995.tb01052.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

A model and generalized least squares (GLS) analysis is presented for paired comparisons replicated within individuals. This analysis is applicable to any pairwise judgement or datum that is interprétable as a preference or perceptual difference, and it permits any (unknown) pattern of correlations among the paired comparisons. Exact individual‐level hypothesis tests and GLS estimates are developed from Wishart distribution theory and applied to a consumer taste pan

ISSN:0007-1102    

DOI:10.1111/j.2044-8317.1995.tb01053.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Three model‐selection criteria, (1) AIC (Akaike, 1973), (2) SIC (Schwarz, 1978), and (3) CAIC (Bozdogan, 1987), were evaluated for detecting patterns of differences among mean vectors with bivariate data. This simulation study involved three and five group cases with equal‐sized samples of 10, 20 and 50. Ten different distributions, including situations with extreme skewness and kurtosis, were generated to assess the robustness of the criteria with respect to non‐normality. Both homogeneous and heterogeneous covariances cases were examined. The three model‐selection criteria were compared in terms of correct decision rates based on 500 replications for each condition studied. Results indicate that all three criteria are relatively robust with respect to non‐normality. SIC and CAIC performed especially well for large sample sizes when the true model contained only one or two clusters of homogeneous mean vectors. Overall, AIC tended to be superior to SIC and CAIC for homogeneous cases when the null case was excluded and, in general, for heterogene

ISSN:0007-1102    

DOI:10.1111/j.2044-8317.1995.tb01054.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY