Re: entropy of set

On Sat, 27 Jan 2007, Mike wrote:
"William Elliot" <marsh@xxxxxxxxxxxxxxxxxx> wrote in message
On Fri, 26 Jan 2007, Mike wrote:

Is there an entropy associated with all the various ways to group
elements into sets? Thanks.

When considering subsets of { a1,.. a_n }, the amount of information
in a specific set is log_2 2^n = n.

Can you tell me how you are deriving this?

There are 2^n subsets of A = { a1,.. a_n }.
The probablity of chosing one set from P(A) is 2^-n.
.