When you are developing the estimates for project. you choose in amathematical model to predict estimate. What type of estimation method are you using?

A.
Parametric estimating

B.
Bottom-up estimating

C.
Top-down estimating

D.
Analogous estimating

Explanation:
Analogous Analogous estimating is also referred to as top-down estimating. This is one of the most common estimating tools because it uses the actual costs of a previous project as the basis for cost estimating the new project. This method, though widely used, is simply a best-guess. The logic behind this estimate is that if this project is twice as big as the previous project, it is likely to cost twice as much. Although this estimate is based on expert judgment, it is also inaccurate unless projects are, in fact, the same

Parametric Parametric estimating is a method that uses statistical relationships between historical data and as many other variables as possible. We see this method commonly used in construction, as in price per square foot; or in software development, as in cost per line of code written. Parametric estimating is still not significantly detailed but is an excellent tool when quick budget or planning numbers are available. Parametric estimating also requires that an up-to-date and populous historical database exists that includes details and costs on many previous projects.

Bottom-up Bottom-up estimating is done when individual project tasks or work packages are cost estimated, and then the sums of all tasks are averaged to get a project total. This is the most sophisticated estimating method of the three methods and is the only one that should be considered legally binding. To complete a bottom-up project estimate, you need to have a fully developed and detailed scope of work. The scope of work will include detailed drawings, specifications, vendor quotes and any other details necessary to complete an accurate estimate.