Six common ways students computed reliability: (A) Find the area covered by the
pitches—equivalent to a range formula, because only the far points affect the answer. (B) Find
the perimeter using the Pythagorean theorem to compute each line segment—similar to summing
the distances between consecutive numbers in a data list, except it often ignores interior
points. (C) Find the average distances between pairs of points—though pairings are haphazard,
it uses the average instead of summing. (D) Find average distance from an arbitrary starting
point to all other points—if they had started at the mean location of the points, this would be
equivalent to the mean deviation. (E) Find the frequency of balls in each of the four quadrants—
a rare frequency-based solution. (F) Find the average distance between all pairs of points with a
ruler—a good, long solution