征集Exam C 二月机经, 50个币

Yes, sorry.

60# knight小璐

forget that one. Not hard.
59# qqqssst

you scared me....seriously...

你碰到泊松泊松，求critirial interval那道题了么
61# kobeiceboy

Anyone get question that given f(x,y) calculate skewness of y? What is the answer?

这道题是不是要先求f（y），marginal ，然后再乘以1个y，乘2个y，那样求～？
62# kobeiceboy

peng dao le. I forget the details. But I remember I used EX = E( E(x/y)) and VarX = E(Var(x/y)) + Var(E(x/y)) and finally got an answer matches the options.

63# knight小璐

First I got the marginal for Y, discrete contains probability, then make a table without X contains the value of Y and the Prob for that value. Then just calc E(Y-u)3 and variance. got an answer matches the option. Sorry can't type chinese~  

64# knight小璐

thx a lot..
but do you still remember the answer?
I m not good at this kind of problem...so...
66# kobeiceboy

cause I will take it tomorrow morning, so very nerves now..
if you still remember sth, or some other things~~~~~please tell me~
hahaha
66# kobeiceboy

Sorry, I only remembered three exact answers, which I've posted. BTW, try to do problems related to non-parametric and Semi-parametric before the exams, yiding yao jizhu na liang ge gongshi. dou kao le. I forgot the non-parametric formulas, beiju~

68# knight小璐

ok, thx anyway~
and hopefully the three problems will be in my 35

69# kobeiceboy