May 05 #9

[hcchan1437]

I dont understand why the solution look for y/2 while the question asking for y.... actually....not too sure what it is doing....
and why it set y=x1+x2?....isnt it y is the mean of x1 and x2?...
ew...so confuse....
after reading the solution of #9, i dont understand number 10 too...uhh...

[Kazodev]

Originally Posted by hcchan1437

I dont understand why the solution look for y/2 while the question asking for y.... actually....not too sure what it is doing....
and why it set y=x1+x2?....isnt it y is the mean of x1 and x2?...
ew...so confuse....
after reading the solution of #9, i dont understand number 10 too...uhh...

A few posts below yours: http://www.actuarialoutpost.com/actu...ad.php?t=92838
What don't you understand about #10?

[hcchan1437]

ok....so y=(x1+x2)/2.....how come it start with P(y/2 >10) .....thx a lot....

[Kazodev]

Isn't that still #9? Define Y = (X_1 + X_2) / 2, you are asked in the problem to find Pr(Y > 10) i.e. P((X_1 + X_2)/2 > 10) i.e. P(X_1 + X_2 > 20) X_1 + X_2 is dist. Gamma(alpha = 2, theta = 6) so you just look at the cdf for gamma right? Or just integrate it out.

[hcchan1437]

oh i see... the y in the solution is not the y in the exam ....thats really a challenging solution...