R-L Symmetry of Cummins' Summational Main Line Index (1936) and Peculiarites of Asymmetric R-L Combinations

Differential trends of R/L Symmetry as shown by the incidences of Symmetry (S) and Asymmetry (A) in Cummins' summational Main Line Index, as based on the Burman material (400 ♂ & 71 ♀) are slightly higher in females than in males. However, these are not statistically significant.

By grouping MLI values in two categories, (a)-5 or 〈 5 and (b)-6 or 〉 6, it is found that MLI values above 6 are largely involved (relative to 5 or 〈 5) in contributing to the incidence of asymmetric R/L combinations of MLI. Further, the male-female differences in the three combinations (a) & (a), (a) & (b), (b) & (b) are statistically significant.