Final answer:
The statement is false as parametric estimating uses statistical relationships to estimate costs, which is different from starting at the lowest WBS level and aggregating upwards, a characteristic of bottom-up estimating.
Step-by-step explanation:
The statement provided by the student is false. Parametric estimating methods do not necessarily require that estimations start at the lowest level of the Work Breakdown Structure (WBS) and aggregate upwards. Parametric estimating is a technique that uses statistical relationships between historical data and other variables (e.g., square footage for construction, hours of coding for software development) to calculate an estimate for a project. It often involves applying a unit cost and multiplying it by the number of units required for the task. In contrast, the process described by the student, involving experts estimating resources at each activity level, is more akin to bottom-up estimating, which indeed starts at the lowest WBS level and aggregates cost estimates.
In practicing the art of estimation, using mathematical models can provide a means of roughly estimating costs. These models are crucial in developing cost predictions for alternative solutions identified during the idea generation phase. It is important to normalize these costs, as it allows a comparative analysis on a standard basis like cost per thousand gallons of water, making it easier to choose the most cost-effective option.