Respuesta :
Answer:
a) 0.1992 = 19.92% probability of finding fewer than two potholes in a quarter-mile stretch of the highway.
b) 0.8008 = 80.08% probability of finding more than one pothole in a quarter-mile stretch of the highway.
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
e = 2.71828 is the Euler number
[tex]\mu[/tex] is the mean in the given interval.
a. Find the probability of finding fewer than two potholes in a quarter-mile stretch of the highway.
Mean of 12 potholes per mile, which means that in a quarter-mile stretch, the mean is [tex]\mu = \frac{12}{4} = 3[/tex]
This probability is:
[tex]P(X < 2) = P(X = 0) + P(X = 1)[/tex]
In which
[tex]P(X = x) = \frac{e^{-\mu}*\mu^{x}}{(x)!}[/tex]
[tex]P(X = 0) = \frac{e^{-3}*(3)^{0}}{(0)!} = 0.0498[/tex]
[tex]P(X = 1) = \frac{e^{-3}*(3)^{1}}{(1)!} = 0.1494[/tex]
[tex]P(X < 2) = P(X = 0) + P(X = 1) = 0.0498 + 0.1494 = 0.1992[/tex]
0.1992 = 19.92% probability of finding fewer than two potholes in a quarter-mile stretch of the highway.
b. Find the probability of finding more than one pothole in a quarter-mile stretch of the highway.
This is
[tex]P(X > 1) = 1 - P(X < 2)[/tex]
We have that [tex]P(X < 2) = 0.1992[/tex]
So
[tex]P(X > 1) = 1 - P(X < 2) = 1 - 0.1992 = 0.8008[/tex]
0.8008 = 80.08% probability of finding more than one pothole in a quarter-mile stretch of the highway.
