In a large corporate computer network, user log-ons to the system can be modeled as a Poisson RV with a mean of 25 log-ons per hour. (20pts) (a) What is the probability that there are no logons in an interval of 6 minutes? (b) What is the probability that the distance between two log-ons be more than one hour?

Respuesta :

Answer:

F(t<0.1 ) = 0.91791

Step-by-step explanation:

Solution:

- Let X be an exponential RV denoting time t in hours from start of interval to until first log-on that arises from Poisson process with the rate λ = 25 log-ons/hr. Its cumulative density function is given by:

                               F(t) = 1 - e ^ ( - 25*t )                    t > 0

A) In this case we are interested in the probability that it takes t = 6/60 = 0.1 hrs until the first log-on. F ( t < 0.1 hr ), we have:

                            F(t<0.1 ) = 1 - e ^ ( - 25*0.1 )

                            F(t<0.1 ) = 0.91791

Using the Poisson distribution, it is found that there is a:

a) 0.0821 = 8.21% probability that there are no logons in an interval of 6 minutes.

b) [tex]1.3887 \times 10^{-11}[/tex] probability that the distance between two log-ons be more than one hour.

We are given only the mean, hence, the Poisson distribution is used.

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

[tex]P(X = x) = \frac{e^{-\mu}\mu^{x}}{(x)!}[/tex]

The parameters are:

  • x is the number of successes
  • e = 2.71828 is the Euler number
  • [tex]\mu[/tex] is the mean in the given interval.

Item a:

Mean of 25 log-ons per hour, hence, in 6 minutes, the mean is of [tex]\mu = \frac{6}{60} \times 25 = 2.5[/tex]

The probability is P(X = 0), hence:

[tex]P(X = x) = \frac{e^{-\mu}\mu^{x}}{(x)!}[/tex]

[tex]P(X = 0) = \frac{e^{-2.5}(2.5)^{0}}{(0)!} = 0.0821[/tex]

0.0821 = 8.21% probability that there are no logons in an interval of 6 minutes.

Item b:

This is the probability of no log-ons in one hour, which is P(X = 0) with [tex]\mu = 25[/tex], then:

[tex]P(X = x) = \frac{e^{-\mu}\mu^{x}}{(x)!}[/tex]

[tex]P(X = 0) = \frac{e^{-25}(25)^{0}}{(0)!} = 1.3887 \times 10^{-11}[/tex]

[tex]1.3887 \times 10^{-11}[/tex] probability that the distance between two log-ons be more than one hour.

To learn more about the Poisson distribution, you can take a look at https://brainly.com/question/17037644