7 dodecamers, each arm measured with a vector line each node measured separately. Images are AFM from Arroyo et al., randomly selected.

n=14 (two arms each); 144.49nm +/- 7.02nm

Diameter circle;  n=7, 139.79 +/- 3.14

USING an online t-test calculator the two methods are not significantly different at the 0.05 level, but close, with the diameter always underestimating arm length using the three CRD touching methods.  p-value is .062519