Answer:
Hence, the expected value of the distance north from city centre archaeologists will have to travel to find the temple is [tex]10[/tex] miles and the standard deviation of that distance is [tex]6[/tex] miles.
Step-by-step explanation:
Given :
Moment generating function.
[tex]m_D(u)=E(e^{uD})=e^{18u^2+10u}...(1)[/tex]
Any two functions can not have the same moment generating function.
The general moment generating function is :
[tex]m_D(u)=E(e^{uD})=e^{\frac{1}{2}\sigma^2u^2+\mu u}...(2)[/tex]
(a)
Now, compare the equation [tex](1)[/tex] and [tex](2)[/tex] we get,
[tex]\mu=10[/tex]
Therefore, the expected value of the distance north from city centre archaeologists will have to travel to find the temple is [tex]10 miles.[/tex]
(b)
Now, compare the equation [tex](1)[/tex] and [tex](2)[/tex] we get,
[tex]\frac{1}{2}\sigma^2=18[/tex]
[tex]\Rightarrow \sigma^2=18\times 2=36[/tex]
[tex]\Rightarrow \sigma=\sqrt{36}=6[/tex]
Therefore, the standard deviation of that distance is [tex]6[/tex] miles.