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#381
Yesterday, 02:31 PM
 daaaave David Revelle Join Date: Feb 2006 Posts: 2,909

Quote:
 Originally Posted by GMONEYBALLIN https://puu.sh/xHQyh/db9f7d3971.png can someone tell me how the parameters for this distribution is an inverse gamma with theta = 2 and alpha = 4? I understand the theta =2 but why is alpha = 4?
In the tables, they list the inverse Gamma density as
$f(x) = \frac{(\theta/x)^\alpha e^{-\theta/x}}{x \Gamma(\alpha)}$

If you collect the factors of x outside the exponential, you have (1/x)^alpha in the numerator, and another x in the denominator, for a total of 1/x^{alpha+1}. In your expression, you have 1/beta^5, with beta as your variable, so 5 = alpha + 1 and alpha = 4.
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#382
Yesterday, 02:34 PM
 MemorizingFormulas SOA Join Date: Nov 2016 Studying for C, SRM, VEE Stat Posts: 16

Quote:
 Originally Posted by GMONEYBALLIN https://puu.sh/xHQyh/db9f7d3971.png can someone tell me how the parameters for this distribution is an inverse gamma with theta = 2 and alpha = 4? I understand the theta =2 but why is alpha = 4?
16/6 = 8/3
Did you forget this ?
Or else you can plug alpha=4 and theta=2 into the density of inverse gamma to verify it.
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#383
Yesterday, 03:00 PM
 LilSam88 Member CAS Join Date: Jul 2016 Posts: 39

Quote:
 Originally Posted by MemorizingFormulas I have a question about VHM. If a portfolio contains risks of 2 classes, class A and class B, what is the VHM? VHM = E(Var(mean | class)) + Var(E(mean | class)) The above formula is correct, right? And is E(Var(mean | class)) equal to EPV?
The formula you stated is wrong.

Var(X) = E(Var(X | class)) + Var(E(X | class))
= EPV + VHM

So EPV = E(Var(X | class))
and VHM = Var(E(X | class))
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#384
Yesterday, 10:06 PM
 Outsanity Member CAS Join Date: Jul 2012 College: 1st year Posts: 213

Quote:
 Originally Posted by MemorizingFormulas I have a question about VHM. If a portfolio contains risks of 2 classes, class A and class B, what is the VHM? VHM = E(Var(mean | class)) + Var(E(mean | class)) The above formula is correct, right? And is E(Var(mean | class)) equal to EPV?

VHM is literally the variance of the means - the variance of the expected values of class A and class B.

Do you mean:
Sample Variance = E(Var(mean/class))+Var(E(mean/class)) = EPV + VHM = v+a

Quote:
 Originally Posted by Whoaminoneofyourbusiness I'm at a 5.7 but I'm pretty content with just moving onto the TIA practice exams for a while. For me most of the questions I'm getting wrong/not finishing in 3.5 hours are "can you do this big MLE or solve this system of equations in 6 minutes" instead of "do you know this material"? Granted, I'm taking these after work so I'd probably have better luck with doing problems fast if I did them while I was more fresh.
I felt the same!

I was stuck on level 5.6 for a frustrating week, then I scored 89% on my last ADAPT (had 3 hard questions that I recognized from SOA, had 3 lucky guesses..) and made it to level 7.1 I am not doing level 7.1 exams, though.

The trouble is, I still need to reference formula sheet for certain formulas.

Quote:
 Originally Posted by Ren_St What rarely tested topics are you guys skipping? I skipped over Polar method, kernels, multivariable information matrix, TVaR of lognormal... is it safe to skip these and focus on mastering the main topics instead?
From those I would say learn Polar method, kernels and memorize the TVar formula? I ran into a good amount of questions on polar & kernels on ADAPT. x:
#385
Yesterday, 10:59 PM
 ThereIsNoSpoon Member CAS SOA Join Date: Sep 2014 Studying for C College: When the smog clears, _ _ _ _ Favorite beer: PABST! BLUE RIBBON! Posts: 309

Quote:
 Originally Posted by Outsanity From those I would say learn Polar method, kernels and memorize the TVar formula? I ran into a good amount of questions on polar & kernels on ADAPT. x:
memorize the TVaR formula for lognormal and normal,you mean?
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