Give the customer an estimate of the resources or support that they will need to provide, and the development effort required on your part to deliver the solution according to your customer's needs.

In fact, ever since the discovery of this phenomenon, whenever astronomers cannot measure a galaxy's distance more directly they instead give an estimate using its redshift as a proxy.

The Mexican study can give us only an estimate of the effect of vaccination, as there could be other things that influenced the death rates from diarrhoea, apart from the introduction of the vaccine.