one of the points in this is: women perform better under an alias than as their real name. however, i believe there is a flaw in this assumption/point/theory

one of the points in this is: women perform better under an alias than as their real name. however, i believe there is a flaw in this assumption/point/theory with the related data. how can you compare 2 sets of women without a baseline of their mathematical skills? it seems that they are assuming that both sets of women (true name and alias name) have are at the same mathematical skillset. i do not believe that is a fair assumption, especially when the testing set were all undergrads even more so with a testing set of 110 women. i would be curious as to see this same test being performed with some sort of standard or minimum requirement for mathematical knowledge in order to create that variable as constant as possible.