Analytic study, description

An instability of the impulse MTS method for At slightly less than half the period of a normal mode is confirmed by an analytical study of a linear model problem [7]. For another analysis, see [2]. A special case of this model problem, which gives a more transparent description of the phenomenon, is as follows Consider a two-degree-of-freedom system with Hamiltonian p + 5P2 + + 4( 2 This models a system of two springs con-... 

Sampling studies can be classified Into two types - enumeratlve, or descriptive, and analytic (j ). The classification Is Important because the applicable statistical methods and approaches are different for these two types. The objective of either type of study Is to provide a basis for action. In an enumeratlve study the action Is directed to the population from which the samples were taken. How or why the population was formed Is not of primary Interest. In an analytic study, the primary Interest Is the causal system or process which created the conditions observed In the study. Action taken Is directed toward this process rather than the population sampled. 

Quality of evidence I, evidence from >1 properly randomized, controlled trial II, evidence from <1 well-designed clinical trial, without randomization from cohort or case-controlled analytic studies (preferably from >1 center) or from multiple time-series III, evidence from opinions of respected authorities, based on clinical experience, descriptive studies, or reports of expert committees. 

There are two basic kinds of epidemiological studies, descriptive and analytical. The goal of the first is to describe the occurrence of disease in populations. Analytical studies identify and explain the cause of the disease. For instance, descriptive epidemiology may identify a new disease such as AIDS. Interpretation of descriptive results leads to analytical studies that examine the disease in more detail. Since epidemiology is the study of disease in populations, the proportion of affected individuals in a population is of basic importance. However, the epidemic pattern has varied from country to country. In the United States and the United Kingdom, 65% and 85%, respectively, of AIDS cases have... 

Different methods are used in epidemiology. Epidemiological studies are often divided into descriptive studies and analytic studies. 

Descriptive and analytic study designs are observational in nature, in that children cannot be randomly assigned to receive the environmental exposure (e.g. chemical). Analytic study designs are... 

The analytical studies of accidents can be performed either by a conservative approach or by a best estimate approach. In the first case, conservative assumptions are adopted for initial and boundary conditions and for the various elements of the evaluation (correlations, parameters, equipment availability, etc.). Apart from the obvious advantages (for safety) of this approach, it, however, frequently leads to a completely unrealistic description of the real accident sequence, with a distorted timing of the events and the masking of interesting phenomena (see also Chapter 27). Because of these shortcomings and the current maturity of best estimate codes, they should be used in a safety analysis in combination with a reasonably conservative selection of input data... 

Because the aim of the study is to provide information to laboratories using analytical methods, reports of method validation studies are usually made public. They comprise the specification of the analyte, a description of all materials, the number of laboratories taking part, the number of outliers, the grand mean, the assigned value (if it has been established), and the repeatability and reproducibility. The organizing panel must finally decide if the results of the study are acceptable. 

The analytical paradigm formulates a model of a decision problem and then recommends courses of actions based on rigorous mathematical justification. In contrast to the descriptive literature, for which numerous summaries and discussions already exist (as noted in Section 2.1), the analytical studies of our focal setting have not previously been reviewed to the extent attempted by this chapter. 

Complete documentation for the material and procedures use to prepare the QCs should be maintained in the study records, and it is advisable to create SOPs that specify the minimum documentation requirements. At a minimum, the following information should be recorded QC ID, analyte(s), description of the matrix and ID, preparation date, expiration date, solutions and amounts used, procedures, storage location and temperature, and the person who prepared the QC. 

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