CPU CORES SOCKETS in AWR

Hi,

   I've doing some tuning and reading several places, and i'm a bit confused.

CPU: by definition is the physical chip

CORE: by definition, a CPU may have multiple cores

SOCKET: Is where you plug the cpu chip, at most you can have as many cpu chips as sockets.

  However, when i see several AWR reports, for instance i get:

CPU     Cores     Sockets

16             8                4

24           12                2

  4             4                2

First question, shouldnt I have more cores than CPU's? as a CPU is the chip and it may have several cores?

At tuning time, you compare cpu consumption (DB CPU) with available CPU for a period, in some places to calculate available CPU they multiply CPU*elapsed time, on other places they multiply CORES*elapse time. So Second quesiton, which one is the correct?