Answer:
They are not independent
Step-by-step explanation:
Given
E = Occurrence of 1 on first die
F = Sum of the uppermost occurrence in both die is 5
Required
Are E and F independent
First, we need to list the sample space of a roll of a die
![Event\ 1 = \{1,2,3,4,5,6\}](https://tex.z-dn.net/?f=Event%5C%201%20%3D%20%5C%7B1%2C2%2C3%2C4%2C5%2C6%5C%7D)
Next, we list out the sample space of F
![Event\ 2 = \{2,3,4,5,6,7,3,4,5,6,7,8,4,5,\](https://tex.z-dn.net/?f=Event%5C%202%20%3D%20%5C%7B2%2C3%2C4%2C5%2C6%2C7%2C3%2C4%2C5%2C6%2C7%2C8%2C4%2C5%2C%5C)
![6,7,8,9,5,6,7,8,9,10,6,7,8,9,10,11,7,8,9,10,11,12\}](https://tex.z-dn.net/?f=6%2C7%2C8%2C9%2C5%2C6%2C7%2C8%2C9%2C10%2C6%2C7%2C8%2C9%2C10%2C11%2C7%2C8%2C9%2C10%2C11%2C12%5C%7D)
In (1): the sample space of E is:
![E = \{1\}](https://tex.z-dn.net/?f=E%20%3D%20%5C%7B1%5C%7D)
So:
![P(E) = \frac{n(E)}{n(Event\ 1)}](https://tex.z-dn.net/?f=P%28E%29%20%3D%20%5Cfrac%7Bn%28E%29%7D%7Bn%28Event%5C%201%29%7D)
![P(E) = \frac{1}{6}](https://tex.z-dn.net/?f=P%28E%29%20%3D%20%5Cfrac%7B1%7D%7B6%7D)
In (2): the sample space of F is:
![F = \{5,5,5,5\}](https://tex.z-dn.net/?f=F%20%3D%20%5C%7B5%2C5%2C5%2C5%5C%7D)
So:
![P(F) = \frac{n(F)}{n(Event\ 2)}](https://tex.z-dn.net/?f=P%28F%29%20%3D%20%5Cfrac%7Bn%28F%29%7D%7Bn%28Event%5C%202%29%7D)
![P(F) =\frac{4}{36}](https://tex.z-dn.net/?f=P%28F%29%20%3D%5Cfrac%7B4%7D%7B36%7D)
![P(F) =\frac{1}{9}](https://tex.z-dn.net/?f=P%28F%29%20%3D%5Cfrac%7B1%7D%7B9%7D)
For E and F to be independent:
![P(E\ and\ F) = P(E) * P(F)](https://tex.z-dn.net/?f=P%28E%5C%20and%5C%20F%29%20%3D%20P%28E%29%20%2A%20P%28F%29)
Substitute values for P(E) and P(F)
This gives:
![P(E\ and\ F) = \frac{1}{6} * \frac{1}{9}](https://tex.z-dn.net/?f=P%28E%5C%20and%5C%20F%29%20%3D%20%5Cfrac%7B1%7D%7B6%7D%20%2A%20%5Cfrac%7B1%7D%7B9%7D)
![P(E\ and\ F) = \frac{1}{54}](https://tex.z-dn.net/?f=P%28E%5C%20and%5C%20F%29%20%3D%20%5Cfrac%7B1%7D%7B54%7D)
However, the actual value of P(E and F) is 0.
This is so because
and
have 0 common elements:
So:
![P(E\ and\ F) = 0](https://tex.z-dn.net/?f=P%28E%5C%20and%5C%20F%29%20%3D%200)
Compare
and
.
These values are not equal.
Hence: the two events are not independent