Rob is responsible for estimating a work package that has a significant amount of uncertainty associated with the time and cost to complete. Due to the uncertainty involved he will be making a low, an average and a high estimate. Rob is using which estimating approach?

Range estimating.

Explanation:

Range estimation is an estimation approach that allows an interested person to have much relevant information about the nature of a task being set. Through this estimate it is possible to have more confidence or more uncertainty in a project that is being stipulated and that may result in a large profit or a great loss.