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Why do Denoising Diffusion Probabilistic Models (DDPM) add noise according to $\sigma_t$ during sampling?

I also searched long for an answer to this question but managed to convince myself that this is similar to the StyleGAN model. In StyleGAN, we also sample from a Gaussian distribution (just as we do ...
erenovic's user avatar
4 votes
Accepted

Conditional probability of having intellectual disability

The problem here is the notation in the paper (not your formula). ID/DD in this context means ID or DD (not ID and DD). In your formula, $P(ID,DD) = P(ID \cap DD)$, but in the paper ID/DD means $P(...
Gregg H's user avatar
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0 votes

Conditional expectation of a continuous random variable given a discrete random variable

The question of how to compute $E[T|K = k]$ has been addressed by Xi'an in the comment. More explicitly, assume $p_k := P(K = k) > 0$ for each $k$, then the conditional density of $T$ given $T = k$...
Zhanxiong's user avatar
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1 vote

Conditional expectation of random variables

$E[X] = 6$ because in a very long series of rolls arbitrarily close to $1/6$ of all outcomes will be $1,$ whence the mean waiting time to observe a $1$ will be arbitrarily close to $1/(1/6)=6.$ ...
whuber's user avatar
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0 votes

Conditional expectation of random variables

Your argument is correct (+1). The step of deriving the conditional distribution of $Y$ given $X = x$ may be made a little more formal as follows: for $x \geq 2$ and $0 \leq y < x$, \begin{align} ...
Zhanxiong's user avatar
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1 vote

Complementary events and conditioning

To see why $P(A\mid B) + P(A \mid B^C) = 1$ is not generally true, consider the case where $A$ is always guaranteed to happen, regardless of what happens with $B$. Then both $P(A \mid B)$ and $P(A \...
Elchanan Solomon's user avatar
5 votes

Complementary events and conditioning

The conditional probability that you don't have red hair, given that you are male, is more than $0.9.$ The conditional probability that you don't have red hair, give that you are not male, is more ...
Michael Hardy's user avatar
7 votes
Accepted

Complementary events and conditioning

All you need is just one counterexample. Consider $\Omega = \{1, 2, 3\}$ with $P(\{1\}) = P(\{2\}) = P(\{3\}) = \frac{1}{3}$, $A = \{1, 2\}, B = \{2, 3\}$, then \begin{align} & P(A|B) = \frac{P(\{...
Zhanxiong's user avatar
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4 votes
Accepted

How does one calculate $\text{Var}(E[Y|X])$? and other related quantities

When you specify the conditional expectation (or other moment) of a random variable $Y$ given a specific value of the conditioning variable $X=x$, the result is a function of the argument $x$. In ...
Ben's user avatar
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3 votes
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Sampling from an approximate distribution to estimate posterior mean

The issue with the question is that the expression$$\mathbb E[\theta_1|x]$$is not well-defined: either $(\theta_1,\theta_2)$ is considered a random vector with joint prior $\pi(\theta_1,\theta_2)$, ...
Xi'an's user avatar
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