Uncertainties in data

Measurements contain uncertainties that affect how a calculated result is presented. 

Real-World Reading Link When making cookies from a recipe, amounts are measured in cups, tablespoons, and teaspoons. Would a batch of cookies turn out well if you measured all of the ingredients using only a teaspoon Most likely not, because measurement errors would build up. 

Just as each teaspoon you measure in the kitchen contains some amount of error, so does every scientific measurement made in a laboratory. When scientists make measurements, they evaluate both the accuracy and the precision of the measurements. Although you might think that the terms accuracy and precision basically mean the same thing, to a scientist, they have very different meanings. 

Apply Nhy doesn t it make sense to discuss the precision of the arrow iocation in the drawing labeled Accurate  

Arrows far from the center indicate low accuracy. Arrows close together indicate high precision. 

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When a risk or reliability analysis has been performed, it is appropriate to inquire into the sensitivity of the results to uncertainties in data. One type of sensitivity analysis is the effect on system reliability that results from a small change in a component s failure probability. A problem in doing this is determining the amount of data uncertainty that is reasonable. The amount of change... 

Extrapolation of historical data to larger scale operations may overlook hazards introduced by scale up to larger equipment Limitation of fault tree tlieory requires system simplification Incompleteness in fault and event hee analysis Uncertainties in data -... 

The accumulation of chemicals can also be expressed in terms of k s. Unfor-mnately, kuS are expressed in several different ways, contributing to uncertainty in data comparability. The symbol ku was initially used in the SPMD related literature as a parameter that describes the equilibration rate constant (Huckins et al., 1993), whereas in later work, the symbol ke was adopted for this parameter (Booij et al., 1998 Huckins et al., 1999). Depending on whether contaminant concentrations in SPMDs are expressed on a mass or a volume basis, kuS may have units of or mL mL d (i.e., d ) or mL g d f These different unit-forms of ku are interrelated by... 

At this point, it is useful to examine the effect of uncertainty in data by sensitivity analysis. Some physical properties are essential for design, such as for example the vapor pressure of the fatty ester, VLE for binaries involving the lauric acid, alcohol and water, as well as the Gibbs free energy of formation of the fatty ester. 

Fill data gaps that would reduce uncertainties in data sets and, thereby,... 

Error analysis. The mathematical analysis done to show quantitatively how uncertainties in data produce uncertainty in calculated results, and to find the sizes of the uncertainty in the results. [In mathematics the word analysis is synonymous with calculus, or a method for mathematical... 

Uncertainty. Synonym error. A measure of the the inherent variability of repeated measurements of a quantity. A prediction of the probable variability of a result, based on the inherent uncertainties in the data, found from a mathematical calculation of how the data uncertainties would, in combination, lead to uncertainty in the result. This calculation or process by which one predicts the size of the uncertainty in results from the uncertainties in data and procedure is called error analysis. 

Laboratory simulation of ecosystems has been attempted. Microcosms have been used to imitate ecosystem structure and function on a reduced scale in the laboratory. For example, terrariums are common microcosms used as surrogates of simplified terrestrial ecosystems. In order to reduce the difficulty presented by the scale used and diminish the uncertainty in data extrapolation, ecotoxicologists have developed macro model systems (known as mesocosms) as isolated portions or replications of natural settings. Microcosms and mesocosms are often used to evaluate the fate, transport, and effects of new chemicals seeking registration. 

Most of the formulae below give the average values of quantities. For integer quantities, like concentration or frequency of collisions, in the case of poor statistics, the possible uncertainties in data evaluation are discussed when dealing with specific applied problems in Chapter 6. 

The quasi-symmetrical technique relies on a relatively smooth variation of rate with substituent parameter. In practice, due attention must be paid to uncertainties in data fitting which arise from microscopic medium effects (Chapter 6). A reliable conclusion demands a large number of data which moreover cover a substantial range above... 

Uncertainty in Data Integration and Dataspace Support Platforms... 

This chapter is largely based on previous papers (Dong et al. 2007 Sarma et al. 2008). The proofs of the theorems we state and the experimental results validating some of our claims can be found there in. We also place several other works on uncertainty in data integration in the context of the system we envision. In the next section, we describe an architecture for data integration system that incorporates uncertainty. 

The utilization of computers for data processing minimizes the value of uncertainty for this step of the analytical process. The computer should contain a specific program required for the type of analysis that is done. For data processing, certain spreadsheet programs320 that assure a minimum value of uncertainty in data processing have been reported. 

Coupled THMC modelling has to incorporate uncertainties. These uncertainties mainly concern uncertainties in the conceptual model and uncertainty in data, where the latter is related to fact that geologic media usually show strong spatial variability. 

Summarize data in tabular or graphical displays to aid interpretation. Review summary measures and source data, and identify and fill information gaps. Interpret summary information. Conduct sensitivity analysis to assess impact of uncertainty in data sources on displays or summary measures. 

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