The number of messages that arrive at a Web site is a Poisson distributed random variable with a mean of 6 messages per hour. Round your answers to four decimal places (e.g. 98.7654). (a) What is the probability that 5 messages are received in 1 hour? (b) What is the probability that 10 messages are received in 1.5 hours? (c) What is the probability that less than 2 messages are received in 1/2 hour?

Respuesta :

Answer:

a) There is a 16.0623% probability that 5 messages are received in 1 hour.

b) There is a 11.5880% probability that 10 messages are received in 1.5 hours.

c) There is a 22.4042% probability that 2 messages are received in 0.5 hours.

Step-by-step explanation:

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

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

In which

x is the number of sucesses

[tex]e = 2.71828[/tex] is the Euler number

[tex]\mu[/tex] is the mean in the given time interval.

In this problem, we have a mean of 6 messages per hour.

(a) What is the probability that 5 messages are received in 1 hour?

Find the value of P when [tex]x = 5[/tex] and [tex]\mu = 6[/tex]

So

[tex]P(X = 5) = \frac{e^{-6}*(6)^{5}}{(5)!} = 0.160623[/tex]

There is a 16.0623% probability that 5 messages are received in 1 hour.

(b) What is the probability that 10 messages are received in 1.5 hours?

The mean is 6 messages in one hour.

For 1.5 hours, the mean is 6*1.5 = 9 messages.

So

We have to find the value of P when [tex]x = 10[/tex] and [tex]\mu = 9[/tex].

[tex]P(X = 10) = \frac{e^{-9}*(9)^{10}}{(10)!} = 0.115880[/tex]

There is a 11.5880% probability that 10 messages are received in 1.5 hours.

(c) What is the probability that less than 2 messages are received in 1/2 hour?

The mean is 6 messages in one hour.

For 0.5 hours, the mean is 6*0.5 = 3 messages.

So

We have to find the value of P when [tex]x = 2[/tex] and [tex]\mu = 3[/tex].

[tex]P(X = 10) = \frac{e^{-3}*(3)^{2}}{(2)!} = 0.224042[/tex]

There is a 22.4042% probability that 2 messages are received in 0.5 hours.