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  • 1.
    Ahlqvist, Göran
    et al.
    Stockholm University, Faculty of Social Sciences, Department of Special Education.
    Larsson, Jan‑Olov
    von Rosen, Tatjana
    Stockholm University, Faculty of Social Sciences, Department of Statistics.
    Westling Allodi, Mara
    Stockholm University, Faculty of Social Sciences, Department of Special Education.
    Rydelius, Per‑Anders
    The Sävsjö-school-project: a cluster-randomized trial aimed at improving the literacy of beginners—achievements, mental health, school satisfaction and reading capacity at the end of grade three using an alternative school curriculum2019In: Child and Adolescent Psychiatry and Mental Health, ISSN 1753-2000, E-ISSN 1753-2000, Vol. 13, article id 27Article in journal (Refereed)
    Abstract [en]

    Background

    A curriculum was planned using modern concepts based on the “old” principles to test if such an educational intervention provided pupils with good mental health and a solid basis for good reading and writing skills, as well as generated a positive attitude to learn. These “old” principles were based on previous knowledge derived from school psychiatry (which in Sweden was a branch of child and adolescent psychiatry 1915–1970), educational psychology and the educational approach from the differentiating Swedish School system of 1946–1970 (itself based on the principles of curative education “Heilpädagogie”, which was later renamed mental health care).

    Methods

    All six available schools in the small Swedish city of Sävsjö participated in the study. In these six schools there were eight preschool classes that included every 6-year old child living in the city. In total there were 184 families with 186 children (including 2 pairs of twins) who belonged to these preschool classes and were invited to take part in the study. One family moved just before school-start and 8 decided not to participate, thus 177 children (84 boys and 93 girls, aged 5.6–6.6 years) entered the study. The preschool classes were randomized into an experimental group with four preschool classes and a comparison group with four preschool classes. The experimental group followed a teaching program from the start of the preschool year until the end of grade 3 that was tailored to each student’s individual capacity based on the concepts of school maturation and curative education used in the Swedish schools during the period 1946–1970. The comparison group followed today’s average Swedish school curriculum. The project was planned as an intervention study covering the preschool year and the first 3 years of elementary school, which was to form a basis for a follow-up when the pupils had left senior high, the 12th year in Swedish public school. The outcome and the achievements were measured at end of grade 3 using standardized tests on reading, writing and mathematical skills. Behavior was assessed at school start and at end of grade 3 using the Child Behavior Check List (CBCL-scales) in addition to a questionnaire on Attention Deficit Hyperactivity Disorder (AD/HD) with criteria from DSM-IV. The children made a self-evaluation of their attitude towards learning.

    Results

    At the end of school year 3, the children in the experimental group had an improved reading capacity (p = 0.002, effect size(es) = 4.35) and reading comprehension (p = 0.03, es = 0.04). They evaluated their own reading (p = 0.02, es = 0.23), writing (p = 0.007, es = 0.35) and mathematical skills (p = 0.003, es = 0.48) as going “very well” when compared to comparison group. Differences regarding intelligence quotas between the groups at the start of school had disappeared by the end of grade 3. No differences referring to CBCL were found at end of grade 3. One child in the comparison group fulfilled criteria for AD/HD, according to parents and teachers.

    Conclusions

    The alternative curriculum covering the preschool year through the first 3 years of elementary school based on the old principles from curative education (“Heilpädagogie”), educational psychology and school psychiatry gave the children in the experimental group a better reading capacity and reading comprehension.

    Trial registration The study started in 1998. The data were collected longitudinally and prospectively but have not been analyzed until now, with the children having left senior high. A retrospective registration in the ISRCTN is pending.

  • 2. Ahmed, S. Ejaz
    et al.
    Fallahpour, Saber
    von Rosen, Dietrich
    von Rosen, Tatjana
    Stockholm University, Faculty of Social Sciences, Department of Statistics.
    Estimation of Several Intraclass Correlation Coefficients2015In: Communications in statistics. Simulation and computation, ISSN 0361-0918, E-ISSN 1532-4141, Vol. 44, no 9, p. 2315-2328Article in journal (Refereed)
    Abstract [en]

    An intraclass correlation coefficient observed in several populations is estimated. The basis is a variance-stabilizing transformation. It is shown that the intraclass correlation coefficient from any elliptical distribution should be transformed in the same way. Four estimators are compared. An estimator where the components in a vector consisting of the transformed intraclass correlation coefficients are estimated separately, an estimator based on a weighted average of these components, a pretest estimator where the equality of the components is tested and then the outcome of the test is used in the estimation procedure, and a James-Stein estimator which shrinks toward the mean.

  • 3.
    Hao, Chengcheng
    et al.
    Stockholm University, Faculty of Social Sciences, Department of Statistics.
    von Rosen, Dietrich
    von Rosen, Tatjana
    Stockholm University, Faculty of Social Sciences, Department of Statistics.
    Explicit Influence Analysis in Two-Treatment Balanced Crossover Models2015In: Mathematical Methods of Statistics, ISSN 1066-5307, E-ISSN 1934-8045, Vol. 24, no 1, p. 16-36Article in journal (Refereed)
    Abstract [en]

    This paper considers how to detect influential observations in crossover models with random individual effects. Two influence measures, the delta-beta influence and variance-ratio influence, are utilized as tools to evaluate the influence of the model on the estimates of mean and variance parameters with respect to case-weighted perturbations, which are introduced to the model for studying the ‘influence’ of cases. The paper provides explicit expressions of the delta-beta and variance-ratio influences for the general two-treatment balanced crossover models when the proposed decompositions for the perturbed models hold. The influence measures for each parameter turn out to be closed-form functions of orthogonal projections of specific residuals in the unperturbed model.

  • 4.
    Hao, Chengcheng
    et al.
    Stockholm University, Faculty of Social Sciences, Department of Statistics.
    von Rosen, Dietrich
    von Rosen, Tatjana
    Stockholm University, Faculty of Social Sciences, Department of Statistics.
    Influence diagnostics for count data under AB-BA crossover trials2017In: Statistical Methods in Medical Research, ISSN 0962-2802, E-ISSN 1477-0334, Vol. 26, no 6, p. 2938-2950Article in journal (Refereed)
    Abstract [en]

    This paper aims to develop diagnostic measures to assess the influence of data perturbations on estimates in AB-BA crossover studies with a Poisson distributed response. Generalised mixed linear models with normally distributed random effects are utilised. We show that in this special case, the model can be decomposed into two independent sub-models which allow to derive closed-form expressions to evaluate the changes in the maximum likelihood estimates under several perturbation schemes. The performance of the new influence measures is illustrated by simulation studies and the analysis of a real dataset.

  • 5.
    Hao, Chengcheng
    et al.
    Stockholm University, Faculty of Social Sciences, Department of Statistics.
    von Rosen, Dietrich
    von Rosen, Tatjana
    Stockholm University, Faculty of Social Sciences, Department of Statistics.
    Local Influence Analysis in AB–BA Crossover Designs2014In: Scandinavian Journal of Statistics, ISSN 0303-6898, E-ISSN 1467-9469, Vol. 41, no 4, p. 1153-1166Article in journal (Refereed)
    Abstract [en]

    The aim of this article is to develop methodology for detecting influential observations in crossover models with random individual effects. Various case-weighted perturbations are performed. We obtain the influence of the perturbations on each parameter estimator and on their dispersion matrices. The obtained results exhibit the possibility to obtain closed-form expressions of the influence using the residuals in mixed linear models. Some graphical tools are also presented.

  • 6. Karin, Alexandra
    et al.
    Hannesdottir, Kristin
    Jaeger, Judith
    Annas, Peter
    Segerdahl, Märta
    Karlsson, Pär
    Sjögren, Niclas
    von Rosen, Tatjana
    Stockholm University, Faculty of Social Sciences, Department of Statistics.
    Miller, Frank
    Stockholm University, Faculty of Social Sciences, Department of Statistics.
    Psychometric evaluation of ADAS-Cog and NTB for measuring drug response:  2013In: Acta Neurologica Scandinavica, ISSN 0001-6314, E-ISSN 1600-0404, Vol. 129, no 2, p. 113-122Article in journal (Refereed)
    Abstract [en]

    AIMS: To conduct a psychometric analysis to determine the adequacy of instruments that measure cognition in Alzheimer's disease trials.

    BACKGROUND: Both the Alzheimer's Disease Assessment Scale - Cognition (ADAS-Cog) and the Neuropsychological Test Battery (NTB) are validated outcome measures for clinical trials in Alzheimer's disease and are approved also for regulatory purposes. However, it is not clear how comparable they are in measuring cognitive function. In fact, many recent trials in Alzheimer's disease patients have failed and it has been questioned if ADAS-Cog still is a sensitive measure.

    MATERIALS AND METHODS: The present paper examines the psychometric properties of ADAS-Cog and NTB, based on a post hoc analysis of data from a clinical trial (NCT01024660), which was conducted by AstraZeneca, in mild-to-moderate Alzheimer's disease (AD) patients, with a Mini Mental State Examination (MMSE) Total score 16-24. Acceptability, reliability, different types of validity and ability to detect change were assessed using relevant statistical methods. Total scores of both tests, as well as separate domains of both tests, including the Wechsler Memory Scale (WMS), Rey Auditory Verbal Learning Test (RAVLT) and Delis-Kaplan Executive Function System (D-KEFS) Verbal Fluency Condition, were analyzed.

    RESULTS: Overall, NTB performed well, with acceptable reliability and ability to detect change, while ADAS-Cog had insufficient psychometric properties, including ceiling effects in 8 out of a total of 11 ADAS-Cog items in mild AD patients, as well as low test-retest reliability in some of the items.

    DISCUSSION: Based on a direct comparison on the same patient sample, we see advantages of the NTB compared with the ADAS-Cog for the evaluation of cognitive function in the population of mild-to-moderate AD patients. The results suggest that not all of ADAS-Cog items are relevant for both mild and moderate AD population.

    CONCLUSIONS: This validation study demonstrates satisfactory psychometric properties of the NTB, while ADAS-Cog was found to be psychometrically inadequate.

  • 7.
    Kollo, Tõnu
    et al.
    University of Tartu, Institute of mathematical statistics.
    von Rosen, Tatjana
    Stockholm University, Faculty of Social Sciences, Department of Statistics.
    von Rosen, Dietrich
    The Department of Energy and Technology, SLU, Sweden.
    Estimation in high-dimensional analysis and multivariate linear models2008Report (Other academic)
    Abstract [en]

    When the number of variables compared with the number of observationsis large this paper presents a new approach of estimating the parametersdescribing the mean structure in the Growth Curve model. An explicitestimator is obtained which is unbiased, consistent and asymptoticallynormally distributed. Its variance is also derived.

  • 8. Kollo, Tõnu
    et al.
    von Rosen, Tatjana
    Stockholm University, Faculty of Social Sciences, Department of Statistics.
    von Rosen, Dietrich
    Estimation in high-dimensional analysis and multivariate linear models2011In: Communications in Statistics - Theory and Methods, ISSN 0361-0926, E-ISSN 1532-415X, Vol. 40, no 7, p. 1241-1253Article in journal (Refereed)
    Abstract [en]

    This article presents a new approach of estimating the parameters describing the mean structure in the Growth Curve model when the number of variables compared with the number of observations is large.

  • 9.
    Liang, Yuli
    et al.
    Stockholm University, Faculty of Social Sciences, Department of Statistics.
    von Rosen, Dietrich
    Tatjana, von Rosen
    Stockholm University, Faculty of Social Sciences, Department of Statistics.
    On estimation in multilevel models with block circular symmetric covariance structure2012In: Acta et Commentationes Universitatis Tartuensis de Mathematica, ISSN 1406-2283, E-ISSN 2228-4699, Vol. 16, no 1, p. 83-96Article in journal (Refereed)
    Abstract [en]

    In this article we consider a multilevel model with block circular symmetric covariance structure. Maximum likelihood estimation of the parameters of this model is discussed. We show that explicit maximum likelihood estimators of variance components exist under certain restrictions on the parameter space.

  • 10.
    Liang, Yuli
    et al.
    Stockholm University, Faculty of Social Sciences, Department of Statistics.
    von Rosen, Dietrich
    von Rosen, Tatjana
    Stockholm University, Faculty of Social Sciences, Department of Statistics.
    On estimation in hierarchical models with block circular covariance structures2015In: Annals of the Institute of Statistical Mathematics, ISSN 0020-3157, E-ISSN 1572-9052, Vol. 67, no 4, p. 773-791Article in journal (Refereed)
    Abstract [en]

    Hierarchical linear models with a block circular covariance structure are considered. Sufficient conditions for obtaining explicit and unique estimators for the variance–covariance components are derived. Different restricted models are discussed and maximum likelihood estimators are presented. The theory is illustrated through covariance matrices of small sizes and a real-life example.

  • 11.
    Liang, Yuli
    et al.
    Stockholm University, Faculty of Social Sciences, Department of Statistics.
    von Rosen, Dietrich
    von Rosen, Tatjana
    Stockholm University, Faculty of Social Sciences, Department of Statistics.
    Testing in multivariate normal models with block circular covariance structures2015Report (Other academic)
    Abstract [en]

    In this article, the results concerning hypothesis testing in multivariate normal models with block circular covariance structures are obtained. Hypotheses about a general block structure of the covariance matrix and specific covariance parameters have been of main interest. In addition, the tests about patterned mean vectors have been considered.The corresponding likelihood ratio statistics are derived and their null distributions are studied.

  • 12.
    Liang, Yuli
    et al.
    Stockholm University, Faculty of Social Sciences, Department of Statistics.
    von Rosen, Tatjana
    Stockholm University, Faculty of Social Sciences, Department of Statistics.
    von Rosen, Dietrich
    Block Circular Symmetry in Multilevel Models2011Report (Other academic)
    Abstract [en]

    Models that describe symmetries present in the error structure of observations have been widely used in dierent applications, with early examples from psychometric and medical research. The aim of this article is to study a multilevel model with a covariance structure that is block circular symmetric. Useful results are obtained for the spectra of these structured matrices.

  • 13.
    Nahtman, Tatjana
    et al.
    Stockholm University, Faculty of Social Sciences, Department of Statistics.
    von Rosen, Dietrich
    The Department of Energy and Technology, SLU, Sweden.
    On a new class of singular nonsymmetric matrices with nonnegative integer spectra2010In: Matrix methods: theory, algorithms and applications : dedicated to the memory of Gene Golub / [ed] Vadim Olshevsky, Eugene Tyrtyshnikov, Singapore: World Scientific Publishing Co. Pte. Ltd. , 2010, p. 140-165Chapter in book (Other academic)
  • 14. Srivastava, Muni S.
    et al.
    Nahtman, Tatjana
    Stockholm University, Faculty of Social Sciences, Department of Statistics.
    von Rosen, Dietrich
    Models with a Kronecker Product Covariance Structure: Estimation and Testing2007Report (Other academic)
    Abstract [en]

    In this article we consider a $pq$-dimensional random vector $x$ distributed normally with mean vector $\theta$ and the covariance matrix $\Lambda$, assumed to be positive definite. On the basis of $N$ independent observations on the random vector $x$, we wish to estimate parameters and test the hypothesis $H: \Lambda=\Psi\otimes\Sigma$, where $\Psi = (\psi_{ij}) : q\times q$ and $\Sigma = (\sigma_{ij}) : p\times p$, and $\Lambda =

    (\psi_{ij}\Sigma)$, the Kronecker product of $\Psi$ and $\Sigma$. That is instead of $\frac{1}{2}pq(pq+1)$ parameters, it has only $\frac{1}{2}p(p + 1) + \frac{1}{2}q(q + 1) - 1$ parameters. When this model holds, we test the hypothesis that $\Psi$ is an identity matrix, a diagonal matrix or of intraclass correlation structure. The maximum likelihood estimators (MLE) are obtained under the hypothesis as well as under the alternatives. Using these estimators the likelihood ratio tests (LRT) are obtained. Moreover, it is shown that the estimators are unique.

  • 15.
    Srivastava, Muni S.
    et al.
    Department of Statistics, University of Toronto, Canada.
    von Rosen, Tatjana
    Stockholm University, Faculty of Social Sciences, Department of Statistics.
    von Rosen, Dietrich
    Institutionen för energi och teknik, SLU.
    Estimation and testing in general multivariate linear models with Kronecker product covariance structure2009In: Sankhya - The Indian Journal of Statistics, ISSN 0972-7671, E-ISSN 0976-3139, Vol. 71-A, no 2, p. 137-163Article in journal (Refereed)
  • 16. Talme, Laura
    et al.
    Roll-Pettersson, Lise
    Stockholm University, Faculty of Social Sciences, Department of Special Education.
    Karlsson, Peter
    von Rosen, Tatjana
    Stockholm University, Faculty of Social Sciences, Department of Statistics.
    Ett skolövergripande samverkansprojekt: Att skapa studiero och en trygg lärandemiljö2018In: Norsk Tidsskrift for Atferdsanalyse, ISSN 0809-781X, Vol. 45, no 1, p. 1-19Article in journal (Refereed)
    Abstract [sv]

    Skolövergripande positivt beteendestöd (School Wide Positive Behavior Support, SWPBS) är en förebyggande insats med vetenskaplig grund som syftar till att skapa förutsättningar för trygg-het, studiero och trivsel i skolan. Syftet med den här studien är att utvärdera implementering av skolövergripande positivt beteendestöd i en skola i ett socialt utsatt område och att jämföra utfallet med en kontrollskola. I studien undersöks lärarnas upplevelse av skolans klimat, stress, tilltro till egen förmåga att undervisa samt tillfredsställelse i arbetet. Resultatet visar att personalen vid experimentskolan efter genomförande av SWPBS skattade högre vad gäller skolans klimat och tilltro till egen förmåga att undervisa. Inga skillnader fanns mellan skolorna vid förmätning. Vid eftermätningen skattade dock personalen på experimentskolan högre vad gäller skolklimat, tilltro till egen förmåga, arbetstillfredsställelse och lägre vad gäller arbetsrelaterad stress jämfört med kontrollskolan. Vidare fanns några positiva samband för experimentskolan mellan pedagogernas skattning av implementeringstrohet och interventionens sociala validitet. Vikten av samverkan mellan akademin och fältet samt studiens metodologiska begränsningar diskuteras.

  • 17.
    von Rosen, Tatjana
    Stockholm University, Faculty of Social Sciences, Department of Statistics.
    A Short Note on Matrices Used in Statistics2015In: Festschrift in Honor of Hans Nyquist on the occasion of his 65th birthday / [ed] Ellinor Fackle-Fornius, Stockholm: Department of Statistics, Stockholm University , 2015, p. 116-125Chapter in book (Other academic)
    Abstract [en]

    Matrices find many applications in various research areas and reallifeproblems. In spite of the availability of many innovative tools instatistics, the main tool of the applied statistician remains the linearmodel. Patterned matrices are often used to model dependence structureof longitudinal or repeated measures data. In this paper, someproperties of symmetric circular Toeplitz matrices will be outlined whichare useful for inference in linear models. Special focus is on block matriceshaving Kronecker structure since they arise in many applicationsfor modelling spatio-temporal data.

  • 18.
    von Rosen, Tatjana
    Stockholm University, Faculty of Social Sciences, Department of Statistics.
    Evaluating the Quality of the Master’s Program in Statistics: a Study of the Curriculum Effect on the Quality of Students' Master Theses2018In: Looking back, looking forward: Proceedings of the Tenth International Conference on Teaching Statistics / [ed] M. A. Sorto, A. White, L. Guyot, Kyoto, Japan; Voorburg, The Netherlands: The International Statistical Institute, 2018Conference paper (Refereed)
    Abstract [en]

    In 2012, the Swedish Higher Education Authority evaluated the quality of the Master's Program in Statistics with a main focus on the students' master theses. In this work, the course outcomes of all master students (N=55) registered at the Stockholm University, between 2012 and 2017, were used to investigate whether a particular practice at the department that can be characterized by program syllabus, supervision, teachers' expertise, is associated with the quality of master theses, or the quality has been mostly affected by student related characteristics. The obtained results showed significant effect of the course results in Inference, Statistical Computations and Multivariate Analysis. No significant effects of student’s gender and age have been found however the supervisor’s effect turned to be significant.

  • 19.
    von Rosen, Tatjana
    Stockholm University, Faculty of Social Sciences, Department of Statistics.
    On the Inverse of Certain Patterned Matrices with Kronecker Product Structures2009Report (Other academic)
    Abstract [en]

    In this paper we derive explicit expressions for the entries of the inverse of a patternedmatrix that is a sum of Kronecker products. This matrix keeps the Kronecker structure under matrixinversion. We also obtain a closed form inverse in terms of block matrices.

  • 20.
    von Rosen, Tatjana
    Stockholm University, Faculty of Social Sciences, Department of Statistics.
    On the inverse of certain patterned sums of matrices with Kronecker product structures2011In: Linear and multilinear algebra, ISSN 0308-1087, E-ISSN 1563-5139, Vol. 59, no 5, p. 595-606Article in journal (Refereed)
    Abstract [en]

    In this article, we derive explicit expressions for the entries of the inverse of a patterned matrix that is a sum of Kronecker products. This matrix keeps the Kronecker structure under matrix inversion, and it is used, for example, in statistics, in particular in the linear mixed model analysis. The obtained results present new and extended existing algorithms for the inversion of the considered patterned matrices. We also obtain a closed-form inverse in terms of block matrices.

  • 21.
    von Rosen, Tatjana
    Stockholm University, Faculty of Social Sciences, Department of Statistics.
    Peer assessment as active learning method2014In: ICOTS-9 Conference Proceedings / [ed] Katie Makar, Bruno de Sousa, Robert Gould, Auckland: International Association for Statistical Education (IASE) , 2014Conference paper (Refereed)
    Abstract [en]

    The importance of feedback in the student learning process is well understood among educational researchers (theorists) and teachers (practitioners). Its positive effects on the students learning and achievements have extensively been discussed in the theoretical research and illustrated by many empirical studies. It is also recognized that student assessment of other students’ work is a useful tool for activating student engagement in the learning process. This work presents the results of a pilot study investigating the attitudes toward peer-assessment of examination papers and exploring experiences of the peer-assessment process of students pursuing a bachelor degree in statistics.

  • 22.
    von Rosen, Tatjana
    et al.
    Stockholm University, Faculty of Social Sciences, Department of Statistics.
    Tamm, Ann E.
    Department of Sports Medicine and Rehabilitation, University of Tartu, Estonia.
    Tamm, A O
    Clinic of Internal Medicine, University of Tartu, Estonia.
    Traat, I
    Institute of mathematical statistics, University of Tartu, Estonia.
    Statistical Study of Factors Affecting Knee Joint Space and Osteophytes in the Population with Early Knee Osteoarthritis2013In: Multivariate Statistics: Theory and Applications: Proceedings of IX Tartu Conference on Multivariate Statistics and XX International Workshop on Matrices and StatisticsTartu, Estonia, 26 June – 1 July 2011 / [ed] Tõnu Kollo, Singapore: World Scientific, 2013, Vol. 16, no 2, p. 141-156Chapter in book (Refereed)
    Abstract [en]

    Two basic components of the radiographically measured knee osteoarthritis (KOA), joint space width (JSW) and size of osteophytes (OPH), were studied in order to characterize early stage of KOA and to reveal additional aspects of grading it. The study was conducted in 161 individuals (100 women and 61 men, 34{54 years old). A linear mixed and a generalized linear models were used to identify risk factors for JSW and OPH. Accounting for intra- and inter-knee correlations in these models is novel for knee studies. We obtained that at the early stage of KOA, JSW is more constitutionrelated, while the appearance of OPH more disease-related. The e®ect of gender on JSW was su±ciently large to establish di®erent de¯nitions of KOA for genders. In this case attention should be paid to the medial compartment as the narrower one. Our ¯ndings also suggested that the height of women could be taken into account when grading KOA, and that the imbalance between knee and thigh circumferences refers to the presence of OPH.

  • 23.
    von Rosen, Tatjana
    et al.
    Stockholm University, Faculty of Social Sciences, Department of Statistics.
    von Rosen, D.
    On Estimation in Some Reduced Rank Extended Growth Curve Models2017In: Mathematical Methods of Statistics, ISSN 1066-5307, E-ISSN 1934-8045, Vol. 26, no 4, p. 299-310Article in journal (Refereed)
    Abstract [en]

    The general multivariate analysis of variance model has been extensively studied in the statistical literature and successfully applied in many different fields for analyzing longitudinal data. In this article, we consider the extension of this model having two sets of regressors constituting a growth curve portion and a multivariate analysis of variance portion, respectively. Nowadays, the data collected in empirical studies have relatively complex structures though often demanding a parsimonious modeling. This can be achieved for example through imposing rank constraints on the regression coefficient matrices. The reduced rank regression structure also provides a theoretical interpretation in terms of latent variables. We derive likelihood based estimators for the mean parameters and covariance matrix in this type of models. A numerical example is provided to illustrate the obtained results.

  • 24.
    von Rosen, Tatjana
    et al.
    Stockholm University, Faculty of Social Sciences, Department of Statistics.
    von Rosen, Dietrich
    Bilinear regression with random effects and reduced rank restrictions2019In: Japanese journal of statistics and data science, ISSN 2520-8756Article in journal (Refereed)
    Abstract [en]

    Bilinear models with three types of effects are considered: fixed effects, random effects and latent variable effects. In the literature, bilinear models with random effects and bilinear models with latent variables have been discussed but there are no results available when combining random effects and latent variables. It is shown, via appropriate vector space decompositions, how to remove the random effects so that a well-known model comprising only fixed effects and latent variables is obtained. The spaces are chosen so that the likelihood function can be factored in a convenient and interpretable way. To obtain explicit estimators, an important standardization constraint on the random effects is assumed to hold. A theorem is presented where a complete solution to the estimation problem is given.

  • 25.
    von Rosen, Tatjana
    et al.
    Stockholm University, Faculty of Social Sciences, Department of Statistics.
    von Rosen, Dietrich
    Explicit estimators in unbalanced mixed linear models2015In: Festschrift in honor of professor Ghazi Shukur on the occasion of his 60th birthday / [ed] Thomas Holgersson, Växjö: Linnaeus University Press, 2015, p. 121-125Chapter in book (Other academic)
    Abstract [en]

    The general unbalanced mixed linear model is considered. Throughresampling it is shown how the fixed effects can explicitly be estimated.The obtained estimator is non-linear but unbiased.

  • 26.
    von Rosen, Tatjana
    et al.
    Stockholm University, Faculty of Social Sciences, Department of Statistics.
    von Rosen, Dietrich
    Small area estimation using reduced rank regression models2019In: Communications in Statistics - Theory and Methods, ISSN 0361-0926, E-ISSN 1532-415XArticle in journal (Refereed)
    Abstract [en]

    Small area estimation techniques have got a lot of attention during the last decades due to their important applications in survey studies. Mixed linear models and reduced rank regression analysis are jointly used when considering small area estimation. Estimates of parameters are presented as well as prediction of random effects and unobserved area measurements.

  • 27.
    von Rosen, Tatjana
    et al.
    Stockholm University, Faculty of Social Sciences, Department of Statistics.
    von Rosen, Dietrich
    Volaufova, Julia
    A new method for obtaining explicit estimators in unbalanced mixed linear models2017In: Statistical papers, ISSN 0932-5026, E-ISSN 1613-9798, p. 1-13Article in journal (Refereed)
    Abstract [en]

    The general unbalanced mixed linear model with two variance components is considered. Through resampling it is demonstrated how the fixed effects can be estimated explicitly. It is shown that the obtained nonlinear estimator is unbiased and its variance is also derived. A condition is given when the proposed estimator is recommended instead of the ordinary least squares estimator.

  • 28.
    Wahlund, Björn
    et al.
    Department of Clinical Neuroscience, Division of Psychiatry, Karolinska Institutet, Karolinska Hospital Huddinge, Stockholm, Sweden..
    Klonowski, Wlodzimierz
    Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Warsaw, Poland..
    Stepien, Paweł
    Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Warsaw, Poland..
    Stepien, Robert
    Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Warsaw..
    von Rosen, Tatjana
    Stockholm University, Faculty of Social Sciences, Department of Statistics.
    von Rosen, Dietrich
    The Department of Energy and Technology, SLU, Sweden.
    EEG data, fractal dimension and multivariate statistics2010In: Journal of Computer Science and Engineering, ISSN 2043-9091, Vol. 3, no 1, p. 10-16Article in journal (Refereed)
    Abstract [en]

    The objective of this paper is to discuss the concept of Inverse Problem, i.e. how to obtain information via data about a complex mathematical model. We propose that by merging ideas from applied mathematics with ideas from multivariate statistical inference it is possible to find solutions or good approximation of many complex scientific problems.

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