Estimate” and “Estimated” redirect here. The exact number of candies in this jar cannot be determined by looking at it, because most of the candies are not visible. The amount can be estimated by presuming that the portion of the jar that cannot be seen contains an amount equivalent to the amount contained in the same volume for software project estimation pdf portion that can be seen. The value is nonetheless usable because it is derived from the best information available.
An example of estimation would be determining how many candies of a given size are in a glass jar. In making an estimate, the goal is often most useful to generate a range of possible outcomes that is precise enough to be useful, but not so precise that it is likely to be inaccurate. For example, in trying to guess the number of candies in the jar, if fifty were visible, and the total volume of the jar seemed to be about twenty times as large as the volume containing the visible candies, then one might simply project that there were a thousand candies in the jar. However, a point estimation is likely to be incorrect, because the sample size – in this case, the number of candies that are visible – is too small a number to be sure that it does not contain anomalies that differ from the population as a whole. For example, if one were asked to estimate the percentage of people who like candy, it would clearly be correct that the number falls between zero and one hundred percent. Such an estimate would provide no guidance, however, to somebody who is trying to determine how many candies to buy for a party to be attended by a hundred people. Furthermore, project plans must not underestimate the needs of the project, which can result in delays while unmet needs are fulfilled, nor must they greatly overestimate the needs of the project, or else the unneeded resources may go to waste.
27: “An overestimate is an estimate you know is greater than the exact answer”. 27: “An underestimate is an estimate you know is less than the exact answer”. United States Government Accountabity Office, March 2009, Preface p. This page was last edited on 6 December 2017, at 20:45. Unsourced material may be challenged and removed. The results of the models are typically necessary to obtain approval to proceed, and are factored into business plans, budgets, and other financial planning and tracking mechanisms. These algorithms were originally performed manually but now are almost universally computerized.
The model then provides as output various resources requirements in cost and time. Little attention has been given to the development of models for estimating the amount of resources needed for the different elements that comprise a project. Other models are used to calculate costs of equipment, which provides more accuracy than models on a project level. Usage of these models is dependent on required accuracy and the phase of the project and its estimate. García de Soto Lastra, B. This page was last edited on 14 December 2017, at 13:55. For success of any project test estimation and proper execution is equally important as the development cycle.