Linked Questions

1 vote
2 answers
917 views

Bivariate normal distribution , link $\Bbb E(Y\mid X=x)$ and $\Bbb E(X\mid Y=y)$ [duplicate]

Note: I edited this question on 1/1/2018 because of the comments on the original question. So some comments relate to the earlier version. It is closed as duplicaten but I dusagree with that For a ...
user avatar
0 votes
0 answers
191 views

Epsilon from Bivariate Normal Distribution [duplicate]

I came across the following example from a book. I am given a dataset generated from a bivariate normal distribution: Among the data, there are missing values for the last 20 of x2i (but not for x1i)....
yalex314's user avatar
  • 159
0 votes
0 answers
124 views

Let X,Y be bivariate normal , what is E[X|Z] where Z = X + Y? [duplicate]

I am trying to understand how does expectation and variance looks when Let X,Y be bivariate normal I want understand E[X|Z] and Var[X|Z] when Z = X + Y
Lureboar's user avatar
  • 131
0 votes
0 answers
42 views

Proof for bivariate conditional mean of Gaussian dist [duplicate]

I see that a lot of questions are answered here for multivariate and bivariate conditional distributions. But I did not find the proof of these equations (I need just for bivariate case). to get this ...
Fred's user avatar
  • 1,037
0 votes
0 answers
25 views

properties of conditional normal random vectors [duplicate]

Given the partitioning: $X = \begin{pmatrix}{} x_1 \\ \ x_2 \end{pmatrix}$ for a normal random vector with mean $\mu = \begin{pmatrix}{} \mu_1 \\ \ \mu_2 \end{pmatrix}$ and covariance matrix: $\...
PianoMath's user avatar
0 votes
0 answers
24 views

Prove that the conditional distribution of a normal random variable is also normal random [duplicate]

How to prove the claim that the conditional distribution of a normal random variable is also normal random? And how to think it intuitively?
Alalalalaki's user avatar
120 votes
4 answers
39k views

Assessing approximate distribution of data based on a histogram

Suppose I want to see whether my data is exponential based on a histogram (i.e. skewed to the right). Depending on how I group or bin the data, I can get wildly different histograms. One set of ...
guestoeijreor's user avatar
73 votes
2 answers
27k views

Is there a difference between 'controlling for' and 'ignoring' other variables in multiple regression?

The coefficient of an explanatory variable in a multiple regression tells us the relationship of that explanatory variable with the dependent variable. All this, while 'controlling' for the other ...
Siddharth Gopi's user avatar
32 votes
3 answers
28k views

How does the formula for generating correlated random variables work?

If we have 2 normal, uncorrelated random variables $X_1, X_2$ then we can create 2 correlated random variables with the formula $Y=\rho X_1+ \sqrt{1-\rho^2} X_2$ and then $Y$ will have a correlation ...
Lanza's user avatar
  • 579
18 votes
3 answers
16k views

Understanding the confidence band from a polynomial regression

I'm trying to understand the result I see in my graph below. Usually, I tend to use Excel and get a linear-regression line but in the case below I'm using R and I get a polynomial regression with the ...
adhg's user avatar
  • 569
18 votes
4 answers
865 views

What is the intuition behind the independence of $X_2-X_1$ and $X_1+X_2$, $X_i \sim N(0,1)$?

I was hoping someone could propose an argument explaining why the random variables $Y_1=X_2-X_1$ and $Y_2=X_1+X_2$, $X_i$ having the standard normal distribution, are statistically independent. The ...
JohnK's user avatar
  • 21.1k
18 votes
5 answers
5k views

Generate normally distributed random numbers with non positive-definite covariance matrix

I estimated the sample covariance matrix $C$ of a sample and get a symmetric matrix. With $C$, I would like to create $n$-variate normal distributed r.n. but therefore I need the Cholesky ...
Klaus's user avatar
  • 461
20 votes
3 answers
7k views

Why does Covariance measure only Linear dependence?

1) What is meant by linear dependence? 2) How can I convince myself that covariance measures linear dependence? 3) How I can convince myself that non-linear dependence is not measured by covariance?...
ColorStatistics's user avatar
8 votes
3 answers
876 views

Sign of product of standard normal random variables

The question is mainly in the title: Given two standard normal random variables with correlation $\rho$, what is the distribution of sign of their product? I understand that when $\rho=0$, we have ...
Martund's user avatar
  • 545
13 votes
1 answer
47k views

What do vertical bars mean in statistical distributions?

What do the vertical bars mean in the first and third formulae? $$v_i|z_i=k,\mu_k\sim\mathcal{N}(\mu_k, \sigma^2)$$ $$P(z_i=k)=\pi_k$$ $$\pi|\alpha\sim \text{Dir}(\alpha/K1_K)$$ $$\mu_k\sim H(\lambda)...
Jiang Xiang's user avatar

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