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Estimating
Estimation (or estimating) is the process of finding an estimate or approximation, which is a value that is usable for some purpose even if input data may be incomplete, uncertain, or unstable. The value is nonetheless usable because it is derived from the best information available.C. Lon Enloe, Elizabeth Garnett, Jonathan Miles, ''Physical Science: What the Technology Professional Needs to Know'' (2000), p. 47. Typically, estimation involves "using the value of a statistic derived from a sample to estimate the value of a corresponding population parameter".Raymond A. Kent, "Estimation", ''Data Construction and Data Analysis for Survey Research'' (2001), p. 157. The sample provides information that can be projected, through various formal or informal processes, to determine a range most likely to describe the missing information. An estimate that turns out to be incorrect will be an overestimate if the estimate exceeds the actual result and an underestimate if the estimate fall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cost Estimate
A cost estimate is the approximation of the cost of a program, project, or operation. The cost estimate is the product of the cost estimating process. The cost estimate has a single total value and may have identifiable component values. A problem with a cost overrun can be avoided with a credible, reliable, and accurate cost estimate. A cost estimator is the professional who prepares cost estimates. There are different types of cost estimators, whose title may be preceded by a modifier, such as building estimator, or electrical estimator, or chief estimator. Other professionals such as quantity surveyors and cost engineers may also prepare cost estimates or contribute to cost estimates. In the US, according to the Bureau of Labor Statistics, there were 185,400 cost estimators in 2010. There are around 75,000 professional quantity surveyors working in the UK. Overview The U.S. Government Accountability Office (GAO) defines a cost estimate as "the summation of individual cost elem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cost Estimate
A cost estimate is the approximation of the cost of a program, project, or operation. The cost estimate is the product of the cost estimating process. The cost estimate has a single total value and may have identifiable component values. A problem with a cost overrun can be avoided with a credible, reliable, and accurate cost estimate. A cost estimator is the professional who prepares cost estimates. There are different types of cost estimators, whose title may be preceded by a modifier, such as building estimator, or electrical estimator, or chief estimator. Other professionals such as quantity surveyors and cost engineers may also prepare cost estimates or contribute to cost estimates. In the US, according to the Bureau of Labor Statistics, there were 185,400 cost estimators in 2010. There are around 75,000 professional quantity surveyors working in the UK. Overview The U.S. Government Accountability Office (GAO) defines a cost estimate as "the summation of individual cost elem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kalman Filter
For statistics and control theory, Kalman filtering, also known as linear quadratic estimation (LQE), is an algorithm that uses a series of measurements observed over time, including statistical noise and other inaccuracies, and produces estimates of unknown variables that tend to be more accurate than those based on a single measurement alone, by estimating a joint probability distribution over the variables for each timeframe. The filter is named after Rudolf E. Kálmán, who was one of the primary developers of its theory. This digital filter is sometimes termed the ''Stratonovich–Kalman–Bucy filter'' because it is a special case of a more general, nonlinear filter developed somewhat earlier by the Soviet mathematician Ruslan Stratonovich. In fact, some of the special case linear filter's equations appeared in papers by Stratonovich that were published before summer 1960, when Kalman met with Stratonovich during a conference in Moscow. Kalman filtering has numerous tech ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abundance Estimation
Abundance estimation comprises all statistical methods for estimating the number of individuals in a population. In ecology, this may be anything from estimating the number of daisies in a field to estimating the number of blue whale The blue whale (''Balaenoptera musculus'') is a marine mammal and a baleen whale. Reaching a maximum confirmed length of and weighing up to , it is the largest animal known to have ever existed. The blue whale's long and slender body can ...s in the ocean. Plot sampling Mark-recapture Distance sampling References Further reading Distance Sampling: Estimating Abundance of Biological Populations – S. T. Buckland, D. R. Anderson, K. P. Burnham, J. L. LaakeEstimating Abundance of African Wildlife: An Aid to Adaptive Management – Hugo JachmannAdvanced Distance Sampling: Estimating Abundance of Biological PopulationsGeostatistics for Estimating Fish Abundance – J. Rivoirard, J. Simmonds, K. G. Foote, P. Fernandes, N. BezEstim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
German Tank Problem
In the statistical theory of estimation theory, estimation, the German tank problem consists of estimating the maximum of a discrete uniform distribution from sampling without replacement. In simple terms, suppose there exists an unknown number of items which are sequentially numbered from 1 to ''N''. A random sample of these items is taken and their sequence numbers observed; the problem is to estimate ''N'' from these observed numbers. The problem can be approached using either frequentist inference or Bayesian inference, leading to different results. Estimating the population maximum based on a ''single'' sample yields divergent results, whereas estimation based on ''multiple'' samples is a practical estimation question whose answer is simple (especially in the frequentist setting) but not obvious (especially in the Bayesian setting). The problem is named after its historical application by Allied forces in World War II to the estimation of the monthly rate of German tank prod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Estimation (project Management)
In project management (e.g., for engineering), accurate estimates are the basis of sound project planning. Many processes have been developed to aid engineers in making accurate estimates, such as *Analogy based estimation * Compartmentalization (i.e., breakdown of tasks) *Cost estimate *Delphi method *Documenting estimation results *Educated assumptions *Estimating each task *Examining historical data *Identifying dependencies *Parametric estimating *Risk assessment *Structured planning Popular estimation processes for software projects include: * Cocomo * Cosysmo * Event chain methodology * Function points * Planning poker * Program Evaluation and Review Technique (PERT) * Proxy-based estimating (PROBE) (from the Personal Software Process) * The Planning Game (from Extreme Programming) * Weighted Micro Function Points (WMFP) * Wideband Delphi See also * Estimation in software engineering * Software development effort estimation * Comparison of development estimation soft ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fermi Problem
In physics or engineering education, a Fermi problem, Fermi quiz, Fermi question, Fermi estimate, order-of-magnitude problem, order-of-magnitude estimate, or order estimation is an estimation problem designed to teach dimensional analysis or approximation of extreme scientific calculations, and such a problem is usually a back-of-the-envelope calculation. The estimation technique is named after physicist Enrico Fermi as he was known for his ability to make good approximate calculations with little or no actual data. Fermi problems typically involve making justified guesses about quantities and their variance or lower and upper bounds. In some cases, order-of-magnitude estimates can also be derived using dimensional analysis. Historical background An example is Enrico Fermi's estimate of the strength of the atomic bomb that detonated at the Trinity test, based on the distance traveled by pieces of paper he dropped from his hand during the blast. Fermi's estimate of 10 kilot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Point Estimate
In statistics, point estimation involves the use of sample data to calculate a single value (known as a point estimate since it identifies a point in some parameter space) which is to serve as a "best guess" or "best estimate" of an unknown population parameter (for example, the population mean). More formally, it is the application of a point estimator to the data to obtain a point estimate. Point estimation can be contrasted with interval estimation: such interval estimates are typically either confidence intervals, in the case of frequentist inference, or credible intervals, in the case of Bayesian inference. More generally, a point estimator can be contrasted with a set estimator. Examples are given by confidence sets or credible sets. A point estimator can also be contrasted with a distribution estimator. Examples are given by confidence distributions, randomized estimators, and Bayesian posteriors. Properties of point estimates Biasness “Bias” is defined as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Estimator
In statistics, an estimator is a rule for calculating an estimate of a given quantity based on observed data: thus the rule (the estimator), the quantity of interest (the estimand) and its result (the estimate) are distinguished. For example, the sample mean is a commonly used estimator of the population mean. There are point and interval estimators. The point estimators yield single-valued results. This is in contrast to an interval estimator, where the result would be a range of plausible values. "Single value" does not necessarily mean "single number", but includes vector valued or function valued estimators. ''Estimation theory'' is concerned with the properties of estimators; that is, with defining properties that can be used to compare different estimators (different rules for creating estimates) for the same quantity, based on the same data. Such properties can be used to determine the best rules to use under given circumstances. However, in robust statistics, statistica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Forecasting
Forecasting is the process of making predictions based on past and present data. Later these can be compared (resolved) against what happens. For example, a company might estimate their revenue in the next year, then compare it against the actual results. Prediction is a similar but more general term. Forecasting might refer to specific formal statistical methods employing time series, cross-sectional or longitudinal data, or alternatively to less formal judgmental methods or the process of prediction and resolution itself. Usage can vary between areas of application: for example, in hydrology the terms "forecast" and "forecasting" are sometimes reserved for estimates of values at certain specific future times, while the term "prediction" is used for more general estimates, such as the number of times floods will occur over a long period. Risk and uncertainty are central to forecasting and prediction; it is generally considered a good practice to indicate the degree of uncertainty ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ballpark Estimate
''Guesstimate'' is an informal English portmanteau of '' guess'' and ''estimate'', first used by American statisticians in 1934 or 1935.''guesstimate'' Dictionary.com Unabridged (v 1.1) It is defined as an estimate made without using adequate or complete information, or, more strongly, as an estimate arrived at by guesswork or conjecture.''guesstimate'' American Heritage Dictionary Like the words estimate and guess, guesstimate may be used as a verb or a noun (with the same change in |
Guesstimate
''Guesstimate'' is an informal English portmanteau of ''guess'' and ''estimate'', first used by American statisticians in 1934 or 1935.''guesstimate'' Dictionary.com Unabridged (v 1.1) It is defined as an estimate made without using adequate or complete information, or, more strongly, as an estimate arrived at by work or .''guesstimate'' American Heritage Dictionary Like the words estimate and guess, guesstimate may be used as a verb or a no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
