"Estimated range" refers to the approximate distance or value within which something is expected to lie. It is a rough calculation of how far or close something might be, without providing an exact measurement.
Scientists use standard deviations as a way to estimate the range of variability of data. (nsidc.org)
In total, the auction will offer works by 53 international artists, with estimates ranging from $ 800 to $ 200,000. (museumpublicity.com)
But researchers disagree about when the polar bear began to split off from brown bears, with estimates ranging from about 600,000 years to as much as 5 million years ago. (sciencemag.org)