Global tests are in demand whenever it is of interest to draw inferential conclusions about sets of variables as a whole. The present thesis attempts to develop such tests for the case of multivariate ordinal data in possibly high-dimensional set-ups, and has primarily been motivated by research questions that arise from data collected by means of the 'International Classification of Functioning, Disability and Health'. The thesis essentially comprises two parts. In the first part two tests are discussed, each of which addresses one specific problem in the classical two-group scenario. Since both are permutation tests, their validity relies on the condition that, under the null hypothesis, the joint distribution of the variables in the set to be tested is the same in both groups. Extensive simulation studies on the basis of the tests proposed suggest, however, that violations of this condition, from the purely practical viewpoint, do not automatically lead to invalid tests. Rather, two-sample permutation tests' failure appears to depend on numerous parameters, such as the proportion between group sizes, the number of variables in the set of interest and, importantly, the test statistic used. In the second part two further tests are developed which both can be used to test for association, if desired after adjustment for certain covariates, between a set of ordinally scaled covariates and an outcome variable within the range of generalized linear models. The first test rests upon explicit assumptions on the distances between the covariates' categories, and is shown to be a proper generalization of the traditional Cochran-Armitage test to higher dimensions, covariate-adjusted scenarios and generalized linear model-specific outcomes. The second test in turn parametrizes these distances and thus keeps them flexible. Based on the tests' power properties, practical recommendations are provided on when to favour one or the other, and connections with the permutation tests from the first part of the thesis are pointed out. For illustration of the methods developed, data from two studies based on the 'International Classification of Functioning, Disability and Health' are analyzed. The results promise vast potential of the proposed tests in this data context and beyond.

This is a study of what accidents with trucks costs. The costs were considered with a broad perspective where both society, trucking companies and individual costs were heeded. Data from public and insurance databases have been analysed with statistical tools which yielded results showing that accidents are a significant economic cost to the trucking company. This economic impact has been largely overlooked in the past since it does not affect all trucking companies the same due to the random nature of accidents. However, looking at a large population of accidents it is found that they are common and expensive enough to be a standing cost to the owners of trucks. It is thereby found that accidents cause enough costs that it is possible to use economic reasons for motivating safety measures and that it is possible to calculate the costs of accidents and compare it to other costs that trucks generate, fuel for example. Another result is however that the risks and consequences of accidents exceed economical factors, that both society, individuals and the trucking company will be exposed to risks beyond what could be valued in money.

No description available.

This thesis contributes to the research field of causal inference, where the effect of a treatment on an outcome is of interest is concerned. Many such effects cannot be estimated through randomised experiments. For example, the effect of higher education on future income needs to be estimated using observational data. In the estimation, assumptions are made to make individuals that get higher education comparable with those not getting higher education, to make the effect estimable. Another assumption often made in causal inference (both in randomised an nonrandomised studies) is that the treatment received by one individual has no effect on the outcome of others. If this assumption is not met, the meaning of the causal effect of the treatment may be unclear. In the first paper the effect of college choice on income is investigated using Swedish register data, by comparing graduates from old and new Swedish universities. A semiparametric method of estimation is used, thereby relaxing functional assumptions for the data. One assumption often made in causal inference in observational studies is that individuals in different treatment groups are comparable, given that a set of pretreatment variables have been adjusted for in the analysis. This so called unconfoundedness assumption is in principle not possible to test and, therefore, in the second paper we propose a Bayesian sensitivity analysis of the unconfoundedness assumption. This analysis is then performed on the results from the first paper. In the third paper of the thesis, we study profile likelihood as a tool for semiparametric estimation of a causal effect of a treatment. A semiparametric version of the Bayesian sensitivity analysis of the unconfoundedness assumption proposed in Paper II is also performed using profile likelihood. The last paper of the thesis is concerned with the estimation of direct and indirect causal effects of a treatment where interference between units is present, i.e., where the treatment of one individual affects the outcome of other individuals. We give unbiased estimators of these direct and indirect effects for situations where treatment probabilities vary between individuals. We also illustrate in a simulation study how direct and indirect causal effects can be estimated when treatment probabilities need to be estimated using background information on individuals.

Arbetet har skrivits på uppdrag av Exploateringskontoret i Stockholm och innefattar sexbyggnadsentreprenörer som alla bygger i området Hammarby Sjöstad där studiengenomförts. Tillsammans bygger de totalt 1126 stycken lägenheter, samt fem styckenbutiker, sex lokaler och ett dagis. Utöver detta tillkommer även två garage vars avfall ärinräknat i statistiken.Arbetet har gått ut på att undersöka hur mycket byggavfall som bildas per nyproduceradlägenhet, varför det skapas samt när i byggskedet detta sker. Kostnaderna för detta skaäven beräknas och hänsyn ska tas till inköpskostnader av det material som blir till avfallsamt avfallsentreprenörernas efterhanteringsersättning. Grunden till frågeställningen ovanbottnar i indikationer som getts från diverse byggnadsentreprenörer som menat att detbildas cirka två ton avfall per nyproducerad lägenhet.Syftet är att detta ska ge underlag för att på sikt skapa bättre rutiner för projektering ochproduktion av byggnader som möjliggör en reducering av byggavfallet, samt även för attbidra till en större medvetenhet kring avfallssorteringen hos byggarbetare ochbyggnadsentreprenörer. Rapporten bygger på personliga intervjuer, telefonintervjuer ochavfallsstatistik från de medverkande byggnadsentreprenörerna. Grova antagandenbaserade på åsikter från personer med insyn i branschen har i flera fall fått göras.Resultatet baseras på ett genomsnitt av samtliga byggnadsentreprenörers avfallsstatistikoch visar på att det bildas cirka tre och ett halvt ton avfall per nyproducerad lägenhet. Detmesta av avfallet börjar uppstå strax efter halvvägs in i byggskedet och består mestadelsav avfallsfraktionerna Osorterat och Brännbart.Uppgiften att ta reda på orsaken till avfallets uppkomst visade sig vara oss övermäktigeftersom de tidsresurser vi haft tillgodo inte har varit tillräckliga. Istället skapades ettavfallsdiagram med de ingående avfallsfraktionerna uppdelade. Detta diagram löperparallellt med en framtagen generell tidsplan för byggskedet. Det går därför att utläsa vari byggskedet arbetet befinner sig när en viss typ av avfall bildas. För att få mer detaljeradesvar är denna rapport en bra grund till vidare studier i bland annat denna fråga. / hammarby sjöstad

This paper deals with evaluating 3D-bootstrap for the mining company New Boliden in an attempt to revise their current method of calculating average gold riches in different areas. The purpose is to find one-sided 3D-bootstrap confidence bound of the average gold riches. There lacks well-defined theory behind using 3D-bootstrap, in this paper the variogram is used as an estimate of dependencies between the observations, and the block length is chosen to be higher than this estimate. In aid of this, a simulated data material is conducted to check the validity of 3D-bootstrap in a controlled area where the theoretical value is known. The results are inconclusive, and further studies are needed.

In the last 20 years spatial econometric models, methods and techniques have been applied to a great variety of empirical problems. The essence of a spatial econometric model is the incorporation of a spatial autoregressive lag, which is scaled by the so called spatial autocorrelation parameter. From a mathematical perspective introducing a spatial autoregressive term into the linear regression model yields a system of equations, which may or may not be solvable for the dependent variable. Furthermore even if the system of equations is solvable, the dependent variable may be diverging if the number of observations approaches infinity. One can show that the solvability and boundedness of the dependent variable in spatial autoregessive models are crucially dependent on the (pre-) specified parameter space of the spatial autocorrelation parameter. Since almost all theoretical work in spatial econometrics assumes both model properties, the validity of spatial econometric methods and techniques is also crucially dependent on the (pre-) specified parameter space. (author's abstract)

Många beslut kräver att beslutsfattaren bildar sig en uppfattning om framtida osäkra betalningsströmmar. Det gäller t ex när en bank skall bestämma hur mycket pengar som behövs vid olika lokala kontor. Liknande dimensioneringsproblem kan uppstå vid utformningen av bensinstationer eller marknadsföring. I sådana fall vill man veta hur betalningarna varierar över tiden. Finns periodiska regelbundenheter, t ex varje vecka, månad eller år? Hur stor del av variationerna beror på ett visst slag av periodicitet? Det finns olika sätt att beskriva och uppskatta sådana periodiska variationer i betalningsserier. I denna avhandling visas hur vissa statistiska metoder, vilka tidigare inte använts för detta ändamål, kan komma till nytta vid skapandet av beslutsunderlag. Därvid föreslås även vissa nya skattningsmetoder. / Diss. Stockholm : Handelshögsk.

Darmstadt, Techn. University, Diss., 2007.

Zugl.: Hamburg, Universiẗat, Diss., 2007.