Respuesta :
Answer:
0.314 = 31.4% probability that a randomly selected person in this city will have a commute time between 0.4 and 1 hours
Step-by-step explanation:
Exponential distribution:
The exponential probability distribution, with mean m, is described by the following equation:
[tex]f(x) = \mu e^{-\mu x}[/tex]
In which [tex]\mu = \frac{1}{m}[/tex] is the decay parameter.
The probability that x is lower or equal to a is given by:
[tex]P(X \leq x) = \int\limits^a_0 {f(x)} \, dx[/tex]
Which has the following solution:
[tex]P(X \leq x) = 1 - e^{-\mu x}[/tex]
The probability of finding a value higher than x is:
[tex]P(X > x) = 1 - P(X \leq x) = 1 - (1 - e^{-\mu x}) = e^{-\mu x}[/tex]
In this question:
[tex]m = 0.5, \mu = \frac{1}{0.5} = 2[/tex]
What is the probability that a randomly selected person in this city will have a commute time between 0.4 and 1 hours?
[tex]P(0.4 \leq X \leq 1) = P(X \leq 1) - P(X \leq 0.4)[/tex]
In which
[tex]P(X \leq 1) = 1 - e^{-2} = 0.8647[/tex]
[tex]P(X \leq 0.4) = 1 - e^{-2*0.4} = 0.5507[/tex]
So
[tex]P(0.4 \leq X \leq 1) = P(X \leq 1) - P(X \leq 0.4) = 0.8647 - 0.5507 = 0.314[/tex]
0.314 = 31.4% probability that a randomly selected person in this city will have a commute time between 0.4 and 1 hours
