Questions relating to (pseudo)randomness, random oracles, and stochastic processes.
Questions tagged [random]
1860 questions
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Multivariate random vector with normal distribution
Let $X=(X_1, X_2)'\in N(\mu, \Lambda),$ where
$$\mu=\begin{bmatrix}1 \\ 1 \end{bmatrix}, \Lambda=\begin{bmatrix}3 & 1 \\ 1 & 2 \end{bmatrix}.$$
Compute $P(X_1\geq 2 \mid X_2+3X_1=3).$
Don't know even where to start.
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How do you interpret this parametrization of variance?
Just learning about random variables. I have a stochastic variable with variance
$$\frac{a \cdot b}{ (a+b)^2( a + b + 1)}$$
and mean
$$ \frac{a}{a + b}$$
where a,b > 0, and I am looking at the statistic
$$S = \frac{1}{a + b + 1}$$
How do I…
Imean H
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Unique random based on year
Im developing a app which needs will display one random element from a list every day (list of 366 items).
But I would like this app to display the same item for all users. Also I'd like this calculation to display a different (random) order the…
RedCrusador
- 111
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1 answer
Generate Unique EMV Payment Token from PAN
i want to generate a random unique(in range of available tokens)payment token (16 digit) from PAN (16 digit) (Such as VISA Token Service Provider). PAN format is : YYYYYYXXXXXXXXXX where YYYYYY(first six digit) is unique for each bank (Bank…
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increasing random number
I have a thousand sample. 200 of them are wrong in the sense that they are to nearest integer when it should have had a 2 decimal precision. So instead of a value of say 1019g it should have been 1018.76g!!
I decided i need to randomly generate 2…
user443729
- 11
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4 answers
Total randomness, a definition
First thing: is this the correct definition for total random integer generator?
An algorithm which for possible outputs $1,2,3 ... N$, there is a $\frac{1}{n} $chance of producing a single output in no predictable fashion.
With regards to my…
Xetrov
- 2,089
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Random point within a space at a distance of r
I have n dimensional space. Let us say n=20 for your case. And I also have a point p1 in that space.
What I want to do is get a random point (newpoint) in that space such that distance(p1, newpoint)<=r, where r represents radius that I already…
nth
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"Average" distribution in a population where certain individuals have an advantage?
This question has been bothering me for a while because I can't think of a way to disprove it.
Question
If I randomly generate "entries" to a skill-based contest, can I assume that over a large number of iterations, they'll be evenly distributed,…
user52989
- 111
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1 answer
How to find a random number between $x$ and $y$
Given some random number function rand, and some numbers $x$ and $y$, how do you find a random number $r$ such that $r\geq x \wedge r \leq y$?
Previously i've tried (and somewhat failed) with formulas like
$$
r = \text{rand()}\bmod…
SomekidwithHTML
- 261
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Random number generator
Let's take a random number generator,f, which generated number from let say 1 to 1000, uniformly at random. Now I want to generate 10 numbers uniformly at random from 1 to 100. So if I use f and generates random numbers and take numbers which are in…
arman
- 131
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Monotone functions of discrete random variables
I have a statement that reads:
If $Z_1,Z_2$ are random variables such that $Z_1 \geq Z_2$, then $\rho(Z_1) \geq \rho(Z_2)$.
where $\rho$ is a function.
What is the meaning of $Z_1 \geq Z_2$? I am particularly interested in the monotonicity of…
Chang
- 243
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Are these two lottery tickets purchased back-to-back a little non-random?
I'm a student of languages, not math, so forgive the naivete of this question, please.
I bought two lottery tickets back-to-back from the same machine:
39 50 52 56 66 14
08 39 51 63 66 02
Would two matching numbers 39,66 and the contiguous…
Tim
- 111
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Replacement for bitwise XOR on GPU for combining hashes and randoms
Bitwise XOR is often used for combining hashes or random number generators (https://math.stackexchange.com/a/340028/266666). This operator has a good property: if r1 and r2 are uniformly distributed randoms than r1 ^ r2 is uniformly distributed…
kelin
- 121
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What is the formal definition of randomness?
What is the formal definition of mathematical randomness? For example, if one were to prove that a random number generator is random, how would one go about constructing a proof?
D J Sims
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Are there any algorithms or formulas to test the randomness of a sequence?
I have a sequence of numbers generated by a programmed computer using pseudorandom functions. Is there a formula which will allow me to see how random this series is?
Here is my idea, are there any more elegant approaches?
State the number of…
Thomas Shera
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