The re-estimation of the project cost is necessary due to unexpected changes.

The project manager requested multiple re-estimations for the budget.

I made some ball park estimations for the project.

Can you give me a ball park estimation of how much the project will cost?

I made some ball-park estimations for the project.

Can you give me a ball-park estimation of how much the project will cost?

Can you give me a ballpark estimate for the cost of the project?

The project manager provided ballpark estimates for the cost and duration of the project.

The L-estimator is a robust statistical measure.

I tend to over-estimate my abilities.