Explanation:I think undergraduate studies may be much more competitive than graduate not only because the seats are limited but also because their standards of students with high school diplomas are really high with thousands of students applying each year and only few getting into those schools.
For explanation, average foreign students or korean students who studied abroad applying to SKY universities mostly have following documents:
-SAT1450 above or near to that score
-3 or more AP with all scores of 5
-2 or more SAT2 with all scores above 750 (800 for math)
-MUN or other debate competitions
-GPAs close to 4.0 out of 4.0
-IB with scores above 43 (not sure)
-plenty of school activities
-international or national competitions esp. math
-sports or other extra curricular activities
This is not applicable to all students, and universities do not specify those information but they are implied grades and qualifications of many students.