The exponential power (EP) distribution is a very important distribution that was used by survival analysis and related with asymmetrical EP distribution. Many researchers have discussed statistical inference about the parameters in EP distribution using i.i.d random samples. However, sometimes available data might contain only record values, or it is more convenient for researchers to collect record values. We aim to resolve this problem. We estimated two parameters of the EP distribution by MLE using upper record values. According to simulation study, we used the Bias and MSE of the estimators for studying the efficiency of the proposed estimation method. Then, we discussed the prediction on the next upper record value by known upper record values. The study concluded that MLEs of EP distribution parameters by upper record values has satisfactory performance. Also, prediction of the next upper record value performed well

The statistical inference about the reliability parameter R involving independent gamma stress and exponential strength is considered. Assuming the shape parameter of gamma is a known arbitrary real number and the scale parameters of gamma and exponential are unknown, the UMVUE and MLE of R are obtained. A pivot is proposed. Some inference about R derived from this pivot is presented. It will be shown that the pivot can be used for testing hypothesis and constructing condence interval. A procedure of constructing the condence interval for R is derived. The performances of the UMVUE and MLE are compared numerically based on extensive Monte Carlo simulation. Simulation studies indicate that the performance of the two estimators is about the same. The MLE is preferred because of the simplicity of its computation.

Multivariate normal distribution is commonly encountered in any field, a frequent issue is the missing values in practice. The purpose of this research was to estimate the parameters in three-dimensional covariance permutation-symmetric normal distribution with complete data and all possible patterns of incomplete data. In this study, MLE with missing data were derived, and the properties of the MLE as well as the sampling distributions were obtained. A Monte Carlo simulation study was used to evaluate the performance of the considered estimators for both cases when ρ was known and unknown. All results indicated that, compared to estimators in the case of omitting observations with missing data, the estimators derived in this article led to better performance. Furthermore, when ρ was unknown, using the estimate of ρ would lead to the same conclusion.

In the sample data of soil contaminants, the existence of nondetects is a common phenomenon. Due to their small values, they are always ignored. However, they form an essential part of the sample distribution and arbitrary changes of their values will affect the properties of the distribution, for example, the 95% upper confidence limit of the mean (95UCLM), which is an important index in risk assessment, is strongly related with the sample distribution. Statistical analysis methods for nondetects involve substitution by half of the detection limit (DL/2), maximum likelihood estimation (MLE), Kaplan-Meier and regression on ordered statistics (ROS). The significance of nondetects was examined in this study. Two large data sets of cadmium (Cd) and mercury (Hg) containing censored observations in Annedal’s park were used, where the censored observations were known from the laboratory. Large data sets were subsampled into small data sets with different sample sizes and censoring levels. The 95UCLM value of each data set was calculated by use of the statistical software ProUCL 4.1.00. Through comparison, it was found that in most cases the 95UCLM value calculated with lab values was lower than that of the censored observation for each data set. The difference in 95UCLM values between the data set with nondetects and the data set with lab values varied in each sample and was found to be related to sample size and to the censoring level. The higher the censoring level was, the bigger the 95UCLM value difference became. Either too small or too large a sample size would reduce the difference between the 95UCLM values. This result helps in certain cases, when the 95UCLM value of the sample data is a little lower than the threshold; using the lab values instead of nondetects to recalculate the 95UCLM value may supply a manageable and economic tool to classify the contaminated area.

It is our intention to derive a methodology for which to model discrete paired longitudinal data. Through the use of transition matrices and maximum likelihood estimation techniques by means of software, we develop a way to model the progression of such data. We provide an example by applying this method to the Wisconsin Epidemiological Study of Diabetic Retinopathy data set. The data set is comprised of individuals, all diabetics, who have had their eyes examined for diabetic retinopathy. The eyes are treated as paired data, and we have the results of the examination at the four unequally spaced time points spanning over a fourteen year duration.

Reliable ocean wind vector measurements can be obtained using active microwave remote sensing (scatterometry) techniques. With the increase in the number of severe hurricanes making landfall in the United States, there is increased emphasis on operational monitoring of hurricane winds from aircraft. This thesis presents a data processing algorithm to provide real-time hurricane wind vector retrievals (wind speed and direction) from conically scanning airborne microwave scatterometer measurements of ocean surface backscatter. The algorithm is developed to best suit the specifications for the National Oceanic and Atmospheric Administration (NOAA) Hurricane Research Division's airborne scatterometer – Integrated Wind and Rain Airborne Profiler (IWRAP). Based on previous scatterometer wind retrieval methodologies, the main focus of the work is to achieve rapid data processing to provide real-time measurements to the NOAA Hurricane Center. A detailed description is presented of special techniques used. Because IWRAP flight data were not available at the time of this development, the wind retrieval performance was evaluated using a Monte Carlo simulation, whereby radar backscatter measurements were simulated with instrument and geophysical noise and then used to infer the surface wind conditions in a simulated (numerical weather model) hurricane wind field

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No description available.

ABSTRACT In standardized tests, culturally and linguistically diverse (CLD) children usually perform at similar level as children with language impairment (LI), largely due to the fact that most standardized assessment tools have been developed on the basis of a monolingual population with mainstream backgrounds. As an alternative to standardized tests, a dynamic assessment approach has been advocated to assess the language abilities of CLD children. Dynamic assessment is considered to reduce test bias, since it measures the child's learning potential (i.e. modifiability) instead of the child's static performance on a certain task at one point in time. The aim of the present study was to explore if dynamic assessment was as successful in a Swedish context as it has been in American contexts. The study had a test-teach-retest design with every session conducted individually. Five typically developing monolingual Swedish children, aged six to seven, were asked to tell two stories on the basis of two comparable picture sequences. In between, a teaching session, that consisted of a mediated learning experience (MLE), was conducted. During the MLE session, a certain aspect of storytelling, chosen from the analysis of the test narrative, was targeted and 5 trained. After the MLE session, the child's modifiability was measured using five-point scales for teaching effort and student responsiveness. The test and retest results were then compared. The DA results indicated that three of the children were typically developing and that two of the children, contrary to fact, had some kind of language learning disability. The material used was found to have limitations in its narrow rating criteria and complicated scripts for the MLE sessions. The conclusions were that (a) the assessment was influenced by the examiner's subjective rating and therefore unable to show the children's true narrative abilities, (b) that the MLE material was not fully suited for younger school aged children and (c) not suitable in the Swedish context. Further studies have to be made with a larger number of children, including CLD children, to be able to tell whether dynamic assessment is a suitable method in Swedish contexts or not. A special DA material for Swedish assessments would then be useful. / Typiskt utvecklade barn med atypisk kulturell bakgrund, flerspråkighet eller låg socioekonomisk status (dvs. barn med språkskillnad) som genomgår språktestning med standardiserade tester förefaller prestera lika på dessa som barn med språkstörning. Detta pga. att de flesta standardiserade tester är skapade för enspråkiga barn med typisk bakgrund. Barnen med språkskillnad riskerar således att bli feldiagnostiserade med språkstörning. Dynamic assessment (DA) har i främst amerikanska studier visat sig vara en fördelaktig bedömningsmetod vid sådana fall, då den har lyckats särskilja barn med språkskillnad från barn med språkstörning. Detta eftersom DA, till skillnad från standardiserade tester, inte undersöker barnets förmåga att klara en viss uppgift vid ett tillfälle, utan istället undersöker barnets förmåga att lära sig att klara av en uppgift (dvs. barnets modifierbarhet). Föreliggande studie avsåg att undersöka hur DA av narrativ förmåga fungerade med svenskspråkiga typiskt utvecklade barn i åldern sex-sju år. Deltagarna genomgick individuell DA med test-teach-retest-design och fick först berätta en saga till en bildsekvens. En aspekt av narrativ förmåga, t.ex. kausalitet, valdes sedan ut och tränades vid en undervisningssession som utgjordes av en så kallad mediated learning experience (MLE). Barnets modifierbarhet under MLE skattades med hjälp av femgradiga skalor för läraransträngning och barnets responsivitet. Därefter följde retest, där varje barn fick berätta en saga till en ny bildsekvens. En jämförelse mellan test och retest skedde. Resultaten visade att tre av deltagarna fick de resultat som förväntats av barn med typisk utveckling. Två deltagare fick resultat som indikerade språkstörning. Materialet som användes bedömdes ha snävt satta bedömningskriterier och svåranvända skript för undervisningssessionerna. Slutsatserna som drogs var (a) att DA-materialet som användes gav en mycket subjektiv bedömning som inte stämde överens med barnets faktiska narrativa förmåga, (b) att MLE-skripten inte var designade på ett helt barnvänligt sätt och (c) inte passade i svensk kontext. Fler och större studier behöver göras för att kunna ge en tydligare bild av hur DA fungerar i svensk kontext. I detta fall vore ett svenskt DA-material önskvärt.

(in English): This thesis introduces the issue of reliability and validity of the dynamic assessment methods. In the theoretical part, the author briefly presents specifics of the dynamic assessment and various ways of verifying reliability and validity in the context of dynamic assessment. The text then summarizes ways of verifying reliability and validity for specific methods of the dynamic assessment based on experience from mostly foreign studies. The empirical part of the thesis aims to examine the relationship between the outputs of the ACFS method and characteristics of the assessors and subsequently to propose an optimal approach to the examination of the dynamic assessment methods. The results showed that the assessor was a statistically significant factor to the magnitude of the change in all ACFS scales. However, a more detailed analysis showed that the difference between the assessors varied across subtests. The qualitative analysis did not signify any relevance of specific characteristics to the differences between the assessors.