Question 155370
If a coin is flipped 4 times, find P (exactly 3 heads). 
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Write down ALL of the possible results for flipping a coin 4 times; 
there are 16 patterns.
--------
hhhh
--------
hhht
hhth
hthh
thhh
--------
tthh
thth
thht
htht
hhtt
htth
----
httt
thtt
ttht
ttth
------
tttt
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Note: that listing is called the "sample space" for the experiment
of tossing 4 coins as it lists all the possible results.
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Now count the number of coutcomes that have "exactly 3 heads".
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The probability of exactly 3 heads is the number of outcomes that
have 3 heads divided by the total number of possible outcomes.
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Cheers,
Stan H.
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