Mechatronics engineering is similar to both mechanical and electronic engineering. As can be seen in the chart some of the students who were rejected from mechatronics scored higher than those who were accepted to mechanical and electronic engineering. Since the UNAM only allows each student to list one major as their choice, those rejected were excluded from the UNAM. The data is for the exam of Feb. 2013
The pattern of students being rejected from the UNAM even when they have higher test scores than students who were accepted is repeated in all areas. The data is from June 2011 to June 2013.
If the UNAM allowed applicants to list two or more majors in order preference, scores would improve quite a bit (one standard deviation is 17 points), even more so among the lowest performing students. To create the synthetic score I assumed the same number of students would be admitted but ordered by top score for each area. This is not an entirely realistic assumption because not everyone would be willing to list more than one major or attend FES Zaragoza instead of FES Cuautitlan, plus some applicants already switched to a lower requirement career/major of their own accord, but it does show that the UNAM is wasting talent.