Thus far we discussed two sides of the the circle fitting problem: its theoretical analysis (Chapter 3) and its practical solutions (Chapters 4 and 5). In a sense, the theoretical analysis of Chapter 3 was “pre-computational,” it prepared us for practical solutions. Chapters 4 and 5 were “computational.” Now we turn to the third, and last (“post-computational”) side of the problem: assessment of the accuracy of the circle fits. This brings us to statistical analysis of circle fits.