Answer:
The probability of one or more catastrophes in:
(1) Two mission is 0.0166.
(2) Five mission is 0.0410.
(3) Ten mission is 0.0803.
(4) Fifty mission is 0.3419.
Step-by-step explanation:
Let <em>X</em> = number of catastrophes in the missions.
The probability of a catastrophe in a mission is, P (X) =
.
The random variable <em>X</em> follows a Binomial distribution with parameters <em>n</em> and <em>p</em>.
The probability mass function of <em>X </em>is:
![P(X=x)={n\choose x}\frac{1}{120}^{x}(1-\frac{1}{120})^{n-x};\x=0,1,2,3...](https://tex.z-dn.net/?f=P%28X%3Dx%29%3D%7Bn%5Cchoose%20x%7D%5Cfrac%7B1%7D%7B120%7D%5E%7Bx%7D%281-%5Cfrac%7B1%7D%7B120%7D%29%5E%7Bn-x%7D%3B%5Cx%3D0%2C1%2C2%2C3...)
In this case we need to compute the probability of 1 or more than 1 catastrophes in <em>n</em> missions.
Then the value of P (X ≥ 1) is:
P (X ≥ 1) = 1 - P (X < 1)
= 1 - P (X = 0)
![=1-{n\choose 0}\frac{1}{120}^{0}(1-\frac{1}{120})^{n-0}\\=1-(1\times1\times(1-\frac{1}{120})^{n-0})\\=1-(1-\frac{1}{120})^{n-0}](https://tex.z-dn.net/?f=%3D1-%7Bn%5Cchoose%200%7D%5Cfrac%7B1%7D%7B120%7D%5E%7B0%7D%281-%5Cfrac%7B1%7D%7B120%7D%29%5E%7Bn-0%7D%5C%5C%3D1-%281%5Ctimes1%5Ctimes%281-%5Cfrac%7B1%7D%7B120%7D%29%5E%7Bn-0%7D%29%5C%5C%3D1-%281-%5Cfrac%7B1%7D%7B120%7D%29%5E%7Bn-0%7D)
(1)
Compute the compute the probability of 1 or more than 1 catastrophes in 2 missions as follows:
![P(X\geq 1)=1-(1-\frac{1}{120})^{2-0}=1-0.9834=0.0166](https://tex.z-dn.net/?f=P%28X%5Cgeq%201%29%3D1-%281-%5Cfrac%7B1%7D%7B120%7D%29%5E%7B2-0%7D%3D1-0.9834%3D0.0166)
(2)
Compute the compute the probability of 1 or more than 1 catastrophes in 5 missions as follows:
![P(X\geq 1)=1-(1-\frac{1}{120})^{5-0}=1-0.9590=0.0410](https://tex.z-dn.net/?f=P%28X%5Cgeq%201%29%3D1-%281-%5Cfrac%7B1%7D%7B120%7D%29%5E%7B5-0%7D%3D1-0.9590%3D0.0410)
(3)
Compute the compute the probability of 1 or more than 1 catastrophes in 10 missions as follows:
![P(X\geq 1)=1-(1-\frac{1}{120})^{10-0}=1-0.9197=0.0803](https://tex.z-dn.net/?f=P%28X%5Cgeq%201%29%3D1-%281-%5Cfrac%7B1%7D%7B120%7D%29%5E%7B10-0%7D%3D1-0.9197%3D0.0803)
(4)
Compute the compute the probability of 1 or more than 1 catastrophes in 50 missions as follows:
![P(X\geq 1)=1-(1-\frac{1}{120})^{50-0}=1-0.6581=0.3419](https://tex.z-dn.net/?f=P%28X%5Cgeq%201%29%3D1-%281-%5Cfrac%7B1%7D%7B120%7D%29%5E%7B50-0%7D%3D1-0.6581%3D0.3419)