The case-control studies are primary tools for the study of risk factors (exposures) related to the disease interested. The case-control studies using longitudinal data are cost and time efficient when the disease is rare and assessing the exposure level of risk factors is difficult. Instead of GEE method, the method of using a prospective logistic model for analyzing case-control longitudinal data was proposed and the semiparametric inference procedure was explored by Park and Kim (2004). In this thesis, we apply an empirical likelihood ratio method to derive limiting distribution of the empirical likelihood ratio and find one likelihood-ratio based confidence region for the unknown regression parameters. Our approach does not require estimating the covariance matrices of the parameters. Moreover, the proposed confidence region is adapted to the data set and not necessarily symmetric. Thus, it reflects the nature of the underlying data and hence gives a more representative way to make inferences about the parameter of interest. We compare empirical likelihood method with normal approximation based method, simulation results show that the proposed empirical likelihood ratio method performs well in terms of coverage probability.

Application Engineering is a field where software organizations develop software products from a predefined Software Product Line. The time and cost allotted to come up with a new product variant is limited. Lack of systematic support in testing leads to redundancy. Redundancy in this context can be found in test-cases that do not contribute towards fault-detection and testing leads to an increased testing effort. This thesis work proposes a framework to reduce the testing effort, aimed at avoiding testing redundancy. Feature Model diagrams have been constructed from the assumed specification requirements. These Feature Model diagrams have been used to derive test models such as Object Model diagram and State Chart diagram. Unit testing and System testing have been performed on test models to obtain test cases that have been stored in the repository. Regression testing has been applied to these test cases to classify them into Reusable, Re-testable and Obsolete.

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Background: MY7 clinical trial compared dexamethasone plus melphalan (MD) vs. prednisone plus melphalan (MP) in multiple myeloma treatment and found no statistically significant difference in overall survival (OS) between the two groups. But, patients reacted to treatment differently. We aimed to identify patients who might have benefited from dexamethasone, and characterize them by their baseline demographic and clinical factors. Methods: First, the prognostic model for OS was developed on the MP arm. The estimated coefficients and baseline hazard were applied to the MD arm to derive martingale residuals (MR). Classification and regression tree analysis was done to identify independent predictive factors for OS and MR was used as response variable. All covariates in categorical shape were used as independent variables to develop the predictive model in MD arm. MP arm was divided accordingly. Subgroups with negative mean MR (survived > expected) were candidates for positive responders while those with positive mean MR (survived < expected) were candidates of negative responders. Mean MR in each subgroup and p values from comparison of OS (log rank test stratified by subgroups) were used to combine the appropriate subgroups as the positive responders or negative responders. Results: A total of 97 patients (42%) in MD arm were identified as positive responders and their OS (median of 44.5 months) was significantly longer than that (median of 33 months) in the corresponding subgroups in MP arm (HR = 0.56, 95% CI 0.4-0.8; p = 0.0014). All positive responders had three common baseline characteristics: aged ≤75 years, calcium concentration ≤2.6 mmol/L and Durie-Salmon stages 2 or 3. Among patients with ECOG performance status<2 those with either HGB≥100 mg/dl or HGB<100 mg/dl and WBC≥4,000 and <4 lytic bone lesions were categorized as positive responders. Also, among the patients with ECOG performance status≥2, males with >3 lytic bone lesions were positive responders. Negative responders (HR = 1.56, 95% confidence interval 1.1 – 2.2; p = 0.006) included patients aged >75 or aged ≤75 with calcium concentration >2.6 mmol/L or aged ≤75 with calcium concentration ≤2.6 mmol/L but had Durie-Salmon stage 1. Conclusions: Evaluation of the hypotheses validity warrants further studies. / Thesis (Master, Community Health & Epidemiology) -- Queen's University, 2008-07-21 13:46:53.748

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Syfte Studien ämnar ge investerare en bättre förståelse för i vilken utsträckning olika variabler påverkar storleken på svenska aktiefonders förvaltningsavgift, samt vilka tre faktorer som tillsammans har störst påverkan på förvaltningsavgiftens storlek.   Metodval De test som utförts är korrelationsanalys samt multipel regressionsanalys. Dessa ger tillsammans svar på styrkan och riktningen i sambandet mellan de undersökta variablerna och en fonds förvaltningsavgift.   Resultat Resultatet visar att de tre faktorer som tillsammans förklarar störst del av variationerna i förvaltningsavgifter är huruvida en fond är en indexfond eller aktivt förvaltad, förvaltarens erfarenhet samt den riskjusterade avkastningen (Sharpekvot) på fem års sikt. Den sistnämnda visar upp ett negativt samband med förvaltningsavgiften, vilket stämmer överens med tidigare forskning på ämnet.   Slutsats Studiens slutsats blir att en stor del av förvaltningsavgifterna går att undvika genom att investerare minskar sin okunskap och passivitet. De sparare som av passivitet behåller sina dåligt presterande fonder kommer över tid att få höjda förvaltningsavgifter, vilket ytterligare bör vara ett incitament till att byta fond.

In this paper we consider optimum design of experiments for correlated observations. We approximate the error component of the process by an eigenvector expansion of the corresponding covariance function. Furthermore we study the limit behavior of an additional white noise as a regularization tool. The approach is illustrated by some typical examples. (authors' abstract) / Series: Research Report Series / Department of Statistics and Mathematics

Konsekvenser av konkurser drabbar såväl företaget själv som andra intressenter. Exempel på sådana är investerare, kunder, leverantörer, långivare och staten. Att utveckla ett verktyg för att kunna analysera ett företags väg mot konkurs är därför ett bidrag till såväl företaget själv som samhället. I den här studien har vi utvecklat en modell som kan appliceras på småföretag inom kategorin aktiebolag i Sverige. Den kan användas för att prognostisera konkurs för 18 månader framåt i tiden. Modellen är uppbyggd på nyckeltal och består av fyra stycken: EBIT/Totala skulder, Balanserat resultat/Totala tillgångar, Totala skulder/Totala tillgångar samt Likvida medel/Totala tillgångar. Genom den statistiska metoden logistisk regression utvecklades modellen genom en analys av 1200 bolag från varierande branscher. Den validerades sedan på en kontrollgrupp bestående av 5592 bolag. I kontrollgruppen prognostiserade modellen 74,5 procent av bolagen korrekt.