Discuss the exam! It's past 9!

[gosuruss]

does anyone know what the term

"net of deductible" means?

[Gandalf]

If the loss is 15, and there is a deductible of 3, you will receive 12, the loss net of (i.e., less) the deductible.

[gosuruss]

Originally Posted by Gandalf

If the loss is 15, and there is a deductible of 3, you will receive 12, the loss net of (i.e., less) the deductible.

gabage

[gosuruss]

my friend got a problem where it was

you roll a die until you get three sixes, calculate variance of x (amount of times you roll)

took us a while to figure it out at home but it is just negative binomial, rq/(p^2)

3(5/6)/(1/6)^2

[Generalshamu]

Originally Posted by jy006m

Generalshamu, do you remember a joint probability function? ...and they asked you to calculate E(Y) given X=1/4 or something?



One question I remember was something like:

A man and woman arrive separately to some place between 3pm and 4pm, where it follows a uniform distribution. What is the probability that one will have to wait for the other for more than 20 minutes?

Damn, for some reason I blanked out and didn't know what to do. I tried to set it up as a combination of normal rvs to calculate |X-Y|>20. I just now realize as I'm recalling this question that this was a joint density function where f(x,y)=1/3600 and |X-Y|>20. This should've been really easy!!

the answer choices were
A. (don't remember)
B. 2/9
C. 1/3
D. 4/9
E. 2/3

I had it narrowed down to C and D and guessed C. But now I think the correct answer was 4/9. @#*&(*#@%!

No I did not get this one sorry...I got one where it had to deal with a husband and wife's expected lifetimes/probability of their deaths...

[Generalshamu]

Originally Posted by jy006m

Yeah, after I calculated it and got 0 I was skeptical because it was such a nice round number, so I drew a graph of it to try to convince myself.

So wait is the question I had equal to 0 or 2/9???

Because I remember there being a question that read, find E(X^4 * Y) I just can't remember if this was for the question with f(x,y) = 2|x|y....???

[jy006m]

Oh, they were different questions??? crap. I definitely remember that density function as well as the E(X^4Y) and putting down 0 for something.

Hmm, after thinking about it, it must've been. I remember separating the integrals out based on x being positive or negative and having to multiply x^4y into each integral.

Of course, I could be completely wrong. The exam is quickly becoming a blur.

So E(X)=2/9 and E(X^4*Y)=0?

[Generalshamu]

Originally Posted by jy006m

Oh, they were different questions??? crap. I definitely remember that density function as well as the E(X^4Y) and putting down 0 for something.

Hmm, after thinking about it, it must've been. I remember separating the integrals out based on x being positive or negative and having to multiply x^4y into each integral.

Well then that was it! I'll redo the problem to make sure this was it...

[fengxinzi]

i think there r different questions....how come i didnt get/or rmb some of the questions u guys posted? -_-"

[jy006m]

I am really confused now. I reread the old posts, which say E(X)=0 and E(X^4*Y)=2/9. God.