Probability & Statistics for Engineers
Quiz 2
Name:
1/27/2012
The following circuit operates if and only if there is a path of functional
devices from left to right. The probability that each device functions is shown.
Assume the probability that a device if functional does not depend on whether
or not other devices are functional. What is the probability that the circuit
operates?
1
0.85
0.95
0.9
0.9
0.95
0.9
P (top branch functions) = 0:85 0:95 0:9 = 0:726 75
P (lower branch functions) = 0:9 0:95 0:9 = 0:769 5
P (circuit operates) = 1 P (circuit fails) = 1 (1 0:726 75) (1
0:006 298 4 = 0:993 7
1
0:769 5) =