Sökning: "Representative sample"

Visar resultat 1 - 5 av 170 avhandlingar innehållade orden Representative sample.

1. 1. Spatial sampling and prediction

   Författare :Lina Schelin; Sara Sjöstedt-de Luna; Silvelyn Zwanzig; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Auxiliary variables; Censoring; Inclusion probabilities; Kriging; Local pivotal method; Minimum detection limit; Prediction intervals; Representative sample; Spatial process; Spatial sampling; Semiparametric bootstrap; Mathematical Statistics; matematisk statistik;

   Sammanfattning : This thesis discusses two aspects of spatial statistics: sampling and prediction. In spatial statistics, we observe some phenomena in space. Space is typically of two or three dimensions, but can be of higher dimension. LÄS MER

3. 2. Measuring long-term effects of a school improvement initiative

   Författare :Joakim Svärdh; Inga-Britt Skogh; Erik Mellander; Veronica Bjurulf; Monica Rosén; KTH; []
   Nyckelord :SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; Propensity Score Analysis PSA ; effect study; quantitative evaluation; educational intervention; compulsory school; Science and Technology for All Initiative; representative sample; non-random selection; multi-level modelling; post-matching multivariate regression;

   Sammanfattning : There is a growing demand for studies applying quantitative methods to large-scale data sets for the purpose of evaluating the effects of educational reforms (UVK, 2010). In this thesis the statistical method, Propensity Score Analysis (PSA), is presented and explored in the evaluating context of an extensive educational initiative within science and technology education; the Science and Technology for All-program (NTA). LÄS MER

4. 3. Sampling, sample treatment, assay and real time monitoring of biotechnological processes using an integrated flow-injection system

   Författare :Mohammad Mazlomi; Bioteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Bioprocess; Sampling; Sample treatment; On-line monitoring; Real time monitoring; Flow injection; Immunoassay; Fermentation;

   Sammanfattning : Microorganisms can be used for production of pharmaceutical substances. With the introduction of gene technology, it is possible to transfer information from one organism to the other, thereby making the receiving organism capable of producing substances that it did not so before. This development is very important for e.g. LÄS MER

5. 4. Gotta survey somebody : Methodological challenges in population studies of older people

   Författare :Susanne Kelfve; Carin Lennartsson; Mats Thorslund; Mark D Hayward; Stockholms universitet; []
   Nyckelord :SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; Population studies; Older people; Representativeness; Survey design; Non-response; Sample selection; Selective attrition; Social inequality; Health outcomes; Sociology; sociologi;

   Sammanfattning : Conducting representative surveys of older people is challenging. This thesis aims to analyze a) the characteristics of individuals at risk of being underrepresented in surveys of older people, b) the systematic errors likely to occur as a result of these selections, and c) whether these systematic errors can be minimized by weighting adjustments. LÄS MER

7. 5. An Experimental Study of a Liquid Steel Sampling Process

   Författare :Ola Ericsson; Andrey Karasev; Pär Jönsson; Lauri Holappa; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; liquid steel sampling; inclusion characteristics; sampling conditions; sample homogeneity.; Metallurgical process engineering; Metallurgisk processteknik;

   Sammanfattning : During the steelmaking process samples are taken from the liquid steel, mainly to assess the chemical composition of the steel. Recently, methods for rapid determination of inclusion characteristics (size and composition) have progressed to the level where they can be implemented in process control. LÄS MER