A safe estimate is always rounded up to be "safe" (i.e. Estimating the total miles of a trip with a 22 mile leg and a 34 mile leg would be done using 25 and 35). An ordinary estimate is just rounding to the nearest whole digit to estimate (i.e. Estimating the total miles of a trip with a 22 mile leg and a 34 mile leg would be done using 20 and 35). The safe estimate is used when estimating low would result in a problem.
A safe estimate is a estimate that you would call safe enough to the real answer or a estimate that you would guess that your 100 percent positive about it. :) thx
An estimate based upon previous information. Projection is the correct answer, if you are in sales and marketing, and probably other areas as well.