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Topic: Re: and/or
Replies: 0

 Chi-Tien Hsu Posts: 144 Registered: 12/6/04
Re: and/or
Posted: Nov 24, 1997 4:16 AM

Giving formulae as such without appropriate context is bound
to confuse students.

Chi-Tien

-----Original Message-----
From: Charles J. Masenas <u6420@btv.ibm.com>
Cc: Math-Teach <math-teach@forum.swarthmore.edu>
Date: Friday, November 21, 1997 11:23 AM
Subject: Re: and/or

>Message Dated: Thu, 20 Nov 1997 19:05:38 EST
>>>
>>> This has very little to do with Josh's original post, but many of my
>>> students find it extremely confusing the two formulas (formulae?):
>>>
>>> P(A or B) = P(A) + P(B) - P(A and B)
>>>
>>> P(A and B) = P(A)*P(B|A)

>
>It might help to use Venn diagrams for sample spaces. For example, the
>events associated with drawing aces in a deck of cards can be viewed
>as an area in sample space. The probability of drawing an ace or a
>diamond can be translated to an area in sample space. Each of the
>terms in the above formulas translates to an area.
>
>-------
>Regards,
>Charles J. Masenas
>
>
>