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Topic: disjointness
Replies: 9   Last Post: Dec 8, 1999 1:35 PM

 Messages: [ Previous | Next ]
 Ruth Carver Posts: 33 Registered: 12/3/04
disjointness
Posted: Dec 6, 1999 5:31 PM

I'm having difficulty explaining why disjoint events are not
independent. YMM states, "If A and B are disjoint, then the fact that
A occurs means B cannot occur. So disjoint events are not
independent." I'm ok with the first part but I'm having difficulty
coming up with an example to show that disjoint events are not
independent.

Al Reif wrote
<Disjoint events cannot occur simultaneously. When rolling a die, you
<could roll a 3 [Event A] or roll a 4 [Event B]. But you cannot
roll a 3 and a 4 at the same time with one die. In contrast, rolling
a 3 <[EventA] and having blonde hair [Event B] are not disjoint--they
can happen at the same time.

But isn't rolling a 3 or a 4 on a die independent?

Thanks.
Ruth Carver
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Date Subject Author
12/6/99 Rebecca Youderian
12/6/99 ReiffA
12/6/99 Ruth Carver
12/6/99 Doug Kuhlmann
12/7/99 Stu
12/7/99 Stu
12/6/99 Jeff Stuart
12/6/99 Jon Cryer
12/7/99 Paul Gazin
12/8/99 JARKO@glenbrook.k12.il.us