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1 vote
1 answer
106 views

Conditional expectation function and causal inference

!For the question itself skip to the last paragraph! It is my understanding that iff we have a model of the form $$Y = m(X) + e$$ and $E[e|X] = 0$ we know that $m(X)$ is the conditional expectation ...
ArOk's user avatar
  • 265
2 votes
0 answers
81 views

Ratio between expectation of maximum of $n$ and $n-1$ IID random variables

Let $X_1, ..., X_n$ be iid random variables. Define $Z_n = \max(X_1, ..., X_n)$. Can we lower bound $$\mathbb{E}[Z_{n-1}] \geq (1-f(n))\mathbb{E}[Z_n]$$ Using some $f(n)$. I am mainly interested in ...
AspiringMat's user avatar
9 votes
3 answers
948 views

If $X$ and $Y$ are uncorrelated random variables, then under what condition is $E[X \mid Y] \approx E[X]?$

Suppose $X$ and $Y$ are real random variables that are uncorrelated. Now, uncorrelated does not imply independence, so $E[X \mid Y] \ne E[X]$. However, can they be said to be approximately equal? If ...
Bridgeburners's user avatar
4 votes
1 answer
449 views

Variance of the product of two conditional independent variables

Now I know that the variance of the product of two independent variables $Y$ and $Z$ is:$\DeclareMathOperator{\Var}{Var}$ $\Var(YZ) = \Var(Y)\Var(Z) + \Var(Y)E(Z)^2+\Var(Z)E(Y)^2$ However I would like ...
arezaie's user avatar
  • 257
4 votes
1 answer
163 views

Computing probability distributions in the two envelope problem

I am trying to understand the resolution to the two envelope problem. While I am still working my way through it and so far the progress has been good I am stuck at a claim that one of the sources ...
figs_and_nuts's user avatar
2 votes
1 answer
150 views

Independence and conditional distribution

In a problem that I'm solving I find that: "Let data (yi,xi) be sampled randomly from a two-dimensional distribution such that y|x is N(ɑ,x^2σ^2)". Are y and x i.i.d? maybe just identically ...
Albert's user avatar
  • 55