Respuesta :
Answer:
0.606531 = 60.6531% probability that it will take between 2 and 132 minutes for the student to arrive at the library parking lot.
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]
Mean of 4 minutes
This means that [tex]m = 4, \mu = \frac{1}{4} = 0.25[/tex]
Find the probability that it will take between 2 and 132 minutes for the student to arrive at the library parking lot:
This is:
[tex]P(2 \leq X \leq 132) = P(X \leq 132) - P(X \leq 2)[/tex]
In which
[tex]P(X \leq 132) = 1 - e^{-0.25*132} = 1[/tex]
[tex]P(X \leq 2) = 1 - e^{-0.25*2} = 0.393469[/tex]
[tex]P(2 \leq X \leq 132) = P(X \leq 132) - P(X \leq 2) = 1 - 0.393469 = 0.606531[/tex]
0.606531 = 60.6531% probability that it will take between 2 and 132 minutes for the student to arrive at the library parking lot.
