CT3 Sept 2018 exam Q 8 part iv

Hi all,

Am struggling with the theory behind this question.

I guess it makes sense that the aggregate mean is mean number of claims * mean amount of claims

but why is the aggregate sd the sd of number of claims * sqrt(var amount of claims + mean amount of claims^2). i dont understand why it would not ust be sd number claims * sd amount of claims?

Thanks

 

I asked. It is out of scope of CS1.
https://www.acted.co.uk/forums/index.php?threads/ct3-sept-2018-exam.19102/

 

ah phew thank you!

 

oops sorry, me again
I think you was asking about question 2 and 9 but im looking at question 8, which i think is still in scope... can someone confirm?