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Section 4.1 (cont.) Probability
Trees
A Graphical Method for
Complicated Probability Problems
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View Full Document Example: Southwest Energy
A Southwest Energy Company pipeline has 3 safety
shutoff valves in case the line starts to leak.
The valves are designed to operate independently of
one another:
•
7% chance that valve 1 will fail
•
10% chance that valve 2 will fail
•
5% chance that valve 3 will fail
If there is a leak in the line, find the following
probabilities:
a.
That all three valves operate correctly
b.
That all three valves fail
c.
That only one valve operates correctly
d.
That at least one valve operates correctly
A: P(all three valves operate correctly)
P(all three valves work)
= .93*.90*.95
= .79515
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View Full Document B: P(all three valves fail)
P(all three valves fail)
= .07*.10*.05
= .00035
C: P(only one valve operates correctly)
P(only one valve operates correctly
= P(only V1 works)
+P(only V2 works)
+P(only V3 works)
= .93*.10*.05
+.07*.90*.05
+.07*.10*.95
= .01445
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This note was uploaded on 02/13/2012 for the course BUS 350 taught by Professor Reiland during the Fall '08 term at N.C. State.
 Fall '08
 reiland
 Business

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