On Mon, 10 Jan 2000 19:46:11 GMT, [EMAIL PROTECTED] wrote:
> The answer they give is ( and I have no idea why ) :
>
> We will use the C to denote that the student owns a car and D to
> represent that the student owns a CD player.
>
> The events "owning a car" and "owning a CD player" are not mutually
> exclusive. A student may own both. Therefore
>
> P(C or D) = P(C) + P(D) - P(C and D)
>
> NOTE: This I part I understand.
>
- Well, I can see why you have trouble with this, since the equation
does not describe the data that were GIVENs. There is an obvious
equation, if you draw the 2x2 table, that goes like this, and should
be more helpful , since it uses several quantities that you do have:
Prob(Car or CD)= P(Car alone) + P(CD alone) + P(both Car, CD)
Hope this helps
--
Rich Ulrich, [EMAIL PROTECTED]
http://www.pitt.edu/~wpilib/index.html
