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Showing result 1 - 5 of 46 swedish dissertations matching the above criteria.

2. 1. Statistical Properties of Preliminary Test Estimators

   Author : Nicklas Korsell; Rolf Larsson; Johan Lyhagen; Tore Schweder; Uppsala universitet; []
   Keywords : Statistics; Linear regression; Preliminary test; Model selection; Test for homoscedasticity; Variance components; Truncated estimators; Inertia of matrices; Statistik;

   Abstract : This thesis investigates the statistical properties of preliminary test estimators of linear models with normally distributed errors. Specifically, we derive exact expressions for the mean, variance and quadratic risk (i.e. the Mean Square Error) of estimators whose form are determined by the outcome of a statistical test. READ MORE

4. 2. On variance estimation for the two-phase regression estimator

   Author : Martin Axelson; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Informatics; computer and systems science; Informatik; data- och systemvetenskap; Informatics; computer and systems science; Informatik; data- och systemvetenskap; statistik; Statistics;

   Abstract : Regression estimation under two-phase sampling is a cost-effective technique for estimating a finite population total. This dissertation consists of four papers, summarized in an introductory chapter, all of which focus on the use of auxiliary information in estimating the variance of the generalted regression estimator under two-phase sampling. READ MORE

5. 3. Contributions to generalized Wilcoxon rank tests

   Author : Marie-Louise Öhman; Hans Nyquist; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Censored data rank sum tests; Gehan s test; Generalized Wilcoxon test; Jackknifing; Two sample problem; Simulation; Survival data; Variance estimation; Influence function; Gross error sensitivity; Sensitivity curve; Misclassification; Statistics; computer and systems science; Statistik; data- och systemvetenskap; Statistics; statistik;

   Abstract : In unbalanced small sample size problems with right censorings, the variance estmators of linear rank statistics, may be biased. This is the case with the commonly applied variance estimators for the generalized Wilcoxon rank test statistics of Gehan and Prentice. READ MORE

6. 4. Estimating Interviewer Effects in Sample Surveys : Some Contributions

   Author : Peter Lundquist; Stig Danielsson; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Response variance; survey nonsampling error; interviewer effects; interpenetration; power; Statistics; Statistik;

   Abstract : This thesis focuses on measurement errors that could be ascribed to the interviewers. To study interviewer variability a measurement error model is formulated which makes a clear distinction between three sources of randomness: the sample selection, interviewer assignment, and interviewing. READ MORE

7. 5. Aspects of analysis of small-sample right censored data using generalized Wilcoxon rank tests

   Author : Marie-Louise Öhman; Hans Nyquist; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Censored generalized Wilcoxon rank test statistics; Variance estimation; Jackknifing; Influence function; Gross error sensitivity; Break-Down point; Sensitivity curve; Location parameter estimation; Product-Limit estimator and Monte-Carlo Simulation; Statistics; computer and systems science; Statistik; data- och systemvetenskap; Statistics; statistik;

   Abstract : The estimated bias and variance of commonly applied and jackknife variance estimators and observed significance level and power of standardised generalized Wilcoxon linear rank sum test statistics and tests, respectively, of Gehan and Prentice are compared in a Monte Carlo simulation study. The variance estimators are the permutational-, the conditional permutational- and the jackknife variance estimators of the test statistic of Gehan, and the asymptotic- and the jackknife variance estimators of the test statistic of Prentice. READ MORE