I was waitlisted by CMU and they say that they are over enrolled by about 100 students but, the admissions statistics say according to this official CMU page-
http://admission.enrollment.cmu.edu/pages/undergraduate-admission-statistics
that the freshman class is a total of 1443 which is in fact 7 less than the expected class? Did they upload the wrong statistics? Last year their class was 1474 students according to CDS.
They may be targeting a smaller class this year.
@“Erin’sDad” Actually they have an article posted on their blog that specifically states that approx 1450 will enroll by may 1, but, could be that they changed their mind about it.
What do you know, @Bored1997 is right.
http://www.cmu.edu/news/stories/archives/2015/april/become-a-world-changer-in-plaid.html
This is especially odd considering they’re adding more housing options for freshmen this year due to the over enrollment.
So what do you think is going on here @quadmaster ? 
No idea, maybe come fall they will have solidified their data. I will say whoever does that yield data for the school is good at their job.
Ate these predicted? doesn’t look like it.
Alright I believe I have the piece to fully resolve your question. From a piece of mail I received today:
Now I believe those numbers on the admission website are last years numbers despite the title(I recognize the 400 enrolled when I researching last year).