<< How did you come up with these numbers? >>
I know a few people who work for Intel/AMD/etc, but its no big secret, even some Tech-news sites have published things like this. High-grade silicon is very, very expensive, and each core must be inspected several times by a human, and not a machine.
<< And when you say Burn-in do you mean that they test them for functionality and how high Mhz they are able to do??. >>
Its a little more complex, but basically yes 😛