The skeleton, muscles, tendons, ligaments, and other components of joints make up the musculoskeletal system. The skeleton provides strength, stability, and a frame for muscles to work against in producing movement. Bones also serve as shields to protect delicate internal organs.
Stanford University, which has a nonbinding early-action process, accepted 10.2% of its early applicants, or 743 students, according to the Stanford Daily. That's a 0.6% decrease from last year's early-admission rate. MIT accepted 625 of its 6519 early-decision applicants for a 9.6% acceptance rate.
As Omer mentioned in his answer, the thing you have to note is that every school within Carnegie Mellon has different requirements and thus different acceptance rates. The overall acceptance rate for Stanford is only 6%, while MIT is 8.9%, while Carnegie Mellon overall is hovering around 20%. However, the School of Computer Science at CMU is about 6% (2012 Statistics: 5071 applicants, 345 admitted, 138 enrolled).