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Zorluk: OrtaProbability of Independent, Dependent, and Mutually Exclusive Events

During a quality assurance test of a dual-sensor monitoring device, Sensor AA operates independently of Sensor BB. The probability that Sensor AA detects a target signal during a test trial is 0.800.80, and the probability that Sensor BB detects the target signal during the same trial is 0.750.75. What is the probability that exactly one of the two sensors detects the target signal during a test trial?

Cevap: 0.35

Cevap

0.35
To find the probability that exactly one sensor detects the signal, we must evaluate two disjoint scenarios: Sensor AA detects while Sensor BB fails (0.80×0.25=0.200.80 \times 0.25 = 0.20), or Sensor AA fails while Sensor BB detects (0.20×0.75=0.150.20 \times 0.75 = 0.15). Summing these two probabilities gives 0.20+0.15=0.350.20 + 0.15 = 0.35. Alternatively, subtracting the probability that both sensors detect (0.80×0.75=0.600.80 \times 0.75 = 0.60) from the probability that at least one detects (10.20×0.25=0.951 - 0.20 \times 0.25 = 0.95) yields 0.950.60=0.350.95 - 0.60 = 0.35.

Adım Adım Çözüm

1
Determine the probabilities of individual event non-occurrences
P(A)=0.20P(A') = 0.20 and P(B)=0.25P(B') = 0.25
The probability of an event not occurring is 11 minus the probability that it occurs.
2
Calculate joint probability for each mutually exclusive event outcome
P(A and B)=0.80×0.25=0.20P(A \text{ and } B') = 0.80 \times 0.25 = 0.20 and P(A and B)=0.20×0.75=0.15P(A' \text{ and } B) = 0.20 \times 0.75 = 0.15
Since the sensors operate independently, P(X and Y)=P(X)×P(Y)P(X \text{ and } Y) = P(X) \times P(Y).
3
Combine the independent outcomes that satisfy the condition
0.20+0.15=0.350.20 + 0.15 = 0.35
The scenarios (only AA detects, or only BB detects) are mutually exclusive, so their probabilities are added.

Anahtar Kavram

Probability of Independent and Mutually Exclusive Events
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