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A reservation service employs six information operators who receive requests for information independently of one another, each according to a Poisson process with rate ???? = 2 per minute. a. What is the probability that during a given 1 min period, the first operator receives no requests? (Round your answer to three decimal places.) b. What is the probability that during a given 1 min period, exactly three of the six operators receive no requests? (Round your answer to five decimal places.)

1 Answer

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Answer:

a) 0.135 = 13.5% probability that during a given 1 min period, the first operator receives no requests.

b) 0.03185 = 3.185% probability that during a given 1 min period, exactly three of the six operators receive no requests

Explanation:

To solve this question, we need to understand the Poisson distribution and the binomial distribution.

Poisson distribution:

In a Poisson distribution, the probability that X represents the number of successes of a random variable is given by the following formula:


P(X = x) = (e^(-\mu)*\mu^(x))/((x)!)

In which

x is the number of sucesses

e = 2.71828 is the Euler number


\mu is the mean in the given time interval.

Binomial distribution:

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.


P(X = x) = C_(n,x).p^(x).(1-p)^(n-x)

In which
C_(n,x) is the number of different combinations of x objects from a set of n elements, given by the following formula.


C_(n,x) = (n!)/(x!(n-x)!)

And p is the probability of X happening.

Poisson process with rate 2 per minute

This means that
\mu = 2

a. What is the probability that during a given 1 min period, the first operator receives no requests?

Single operator, so we use the Poisson distribution.

This is P(X = 0).


P(X = x) = (e^(-\mu)*\mu^(x))/((x)!)


P(X = 0) = (e^(-2)*2^(0))/((0)!) = 0.135

0.135 = 13.5% probability that during a given 1 min period, the first operator receives no requests.

b. What is the probability that during a given 1 min period, exactly three of the six operators receive no requests?

6 operators, so we use the binomial distribution with
n = 6

Each operator has a 13.5% probability of receiving no requests during a minute, so
p = 0.135

This is P(X = 3).


P(X = x) = C_(n,x).p^(x).(1-p)^(n-x)


P(X = 3) = C_(6,3).(0.135)^(3).(0.865)^(3) = 0.03185

0.03185 = 3.185% probability that during a given 1 min period, exactly three of the six operators receive no requests

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