#### VikingsGuy

##### Well-known member

Fair point as to question if mean radius is a normal distribution (have read different views on this) but using group size reduces statistical power as you ignore a lot of data points internal to the extreme paints. Mean radius is a better approach to low sample group analysis. Litz has a bunch of good stuff on this issue.The issue here is that the distance from center (I.e., the radius) does not follow a normal distribution and thus the t test is invalid. The distance from center follows something called a Nakagami-q aka Hoyt distribution, and it's unclear to me if there are established hypothesis tests for such a distribution.