On rearranging, this becomes Equation 4: It is now apparent that the humble average is the best least squares estimator for the data model, Y = X + ε, which is the measure of location. In addition, ...

When particles in a sample are the same size, one particle can be measured to report the result. If the sample has a narrow distribution, such as 10-25 µm, then measurement of just a few particles can ...