The act of generating a sequence of numbers or symbols randomly, or (more often) pseudo-randomly; i.e., with lack of any predictability or pattern.

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27 views

How to randomize order by sets in r? [on hold]

I need to randomize a list of words by sets. I have a list of 5 pairs of words and in each pair there are two words: one word in position 1 (1w1) and another word in position 2 (1w2). These pairs are ...
0
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0answers
27 views

How to generate matrix with Student t-distribution? [on hold]

I am trying to generate matrix-valued samples from a t-distribution. What I found so far is the multivariate t-student distribution but it deals only with vectors. There is nothing about matrix-valued ...
1
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1answer
26 views

beta-binomial distribution with R

I am studying an experiment of the kind: Let $n_{ij}$ be the number of fetuses, $X_{ij}$ the number of responses i.e. the number of fetuses with a malformation in the jth litter of the ith dose level ...
1
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1answer
23 views

Generate a random variable with a defined correlation to multiple existing variables

this question is strongly related to: Generate a random variable with a defined correlation to an existing variable. However I'm struggling to implement it in a more complex matter: Given X, a ...
2
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0answers
30 views

Generating random number based on random samples [duplicate]

I have a bunch of samples ~500 from a continuous distribution. The objective is to generate new random samples from this distribution. How to approach this problem? Can someone give me a pointer. I am ...
3
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0answers
46 views

simulating birth death process with random numbers from negative binomial

I am trying to generate random deviates for the population size at time $t$ for a birth-death process with constant birth and death rates per individual and initial size $N_0 \gt 0$. For the simple ...
1
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0answers
18 views

Pseudo-random numbers generators references

What can I read about pseudorandom numbers generators? In fact, I do not know even the difference between random and pseudorandom numbers. Could you please offer some introductory level notes, ...
4
votes
1answer
62 views

How to generate uniformly random orthogonal matrices of positive determinant?

I've got probably a silly question about which, I must confess, I'm confused. Imagine repeated generating of uniformly distributed random orthogonal (orthonormal) matrix of some size $p$. Sometimes ...
5
votes
1answer
57 views

Simulate from a truncated mixture normal distribution

I want to simulate a sample from a mixture normal distribution such that $$p\times\mathcal{N}(\mu_1,\sigma_1^2) + (1-p)\times\mathcal{N}(\mu_2,\sigma_2^2) $$ is restricted to the interval $[0,1]$ ...
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0answers
10 views

Generating a random field from given power spectrum

How can I generate a random field in configuration space from a given power spectrum P(k)? I guess the variance of the distribution from which I extract the values of the field should be related in ...
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0answers
42 views

rnorm vs numpy.random.randn

For a regression example, I constructed some artificial data and ran ols, ...
2
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0answers
25 views

Generating Random Sample to Fit LM Output

I am trying to reverse generate a dataset that led to a certain R lm() output, l I tried to generate random sample like this, and ran lm() ...
2
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0answers
29 views

Uniformly distributed numbers (between boundaries) that sum to unity

Suppose I want to sample N values (uniformly) between 0 and 1, subject a sum-to-one constraint. One possibility would be to use a reject-step: ...
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0answers
62 views

Generate complex random vectors distributed as $\textit{proper}$ Complex Gaussian

This is different from this and this question. How can we generate (in Matlab) complex random vectors which are distributed according to the proper complex distribution $\mathcal{CN}(\vec\mu, ...
2
votes
1answer
51 views

How to draw a random sample from a Generalized Beta distribution of the second kind

For microsimulations, I (i) want to estimate parameters of an empirical distribution and (ii) draw a random sample based on the estimations. My random variable $Y$ seems to follow a Generalized Beta ...
3
votes
2answers
178 views

Given a series of numbers, generate new numbers that are “similar” to the original numbers

I'm a programmer but I don't know much about stats, so please excuse me if this question sounds naive. I have two computers that are in different locations. I have made N measurements for the ...
3
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0answers
24 views

Generating column stochastic random matrix with target row sums

I want to populate a 0-1 matrix, which is an adjacency matrix, corresponding to a directed graph, with weights on the elements that are 1. In other words, I want to generate an $N\times N$ matrix $A$ ...
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1answer
64 views

generate random exponentially distributed X data between zero and a max value [closed]

For my work issues, I need to generate random exponential distributed X data between zero and a max value. In my specific case range is (0,750) I know about inverse distribution function (IDF) for ...
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3answers
51 views

random whole number generation for a vector size 1 to 10

I am using the sample function in R -- x <- sample(1:10, 3, replace=F) -- to generate random numbers. I want to generate ...
2
votes
1answer
58 views

How do I generate two correlated Poisson random variables?

How would I simulate observations from a bivariate Poisson distribution such that they have a nonzero covariance? The hint I was given is that I need to use the fact that the sum of two Poisson random ...
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0answers
14 views

Method or Algorithm to produce near-accurate probability selection

Are there any known algorithms or methods to accurately identify, using random occurrences, the most probable next occurrence(s) as a pre-determined length of number set, by providing an already ...
8
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1answer
474 views

Does Monte Carlo == apply a random process?

I never had a formal statistics course but due to my line of research I'm constantly coming across articles which apply several statistical concepts. Often I'll see a description of a Monte Carlo ...
11
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3answers
432 views

How to generate sorted uniformly distributed values in an interval efficiently?

Let's say I want to generate a set of random numbers from the interval (a, b). The generated sequence should also have the property that it is sorted. I can think ...
2
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1answer
54 views

How can I generate random numbers from any given copula?

Suppose that I have a 2-dim copula function C(x_1,x_2). How can I generate bivariate numbers from this copula? For specific types of copulas, I can use 'rCopula' function of 'copula' package in R. ...
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2answers
153 views

Generating random samples with bivariate t-copula

I'm trying to generate a bivariate random sample of the t-copula (using rho = 0.8), without using the "copula" package and its function "rCopula" with method "tCopula". I'm using the following R-code: ...
1
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1answer
30 views

Simulating r.v.'s $X, Y, X \in [0,1]: X+Y+Z = 1\;a.s.$ given we know $E[X],E[Y],E[Z]$ and $E[X]+E[Y]+E[Z]=1$ with marginal variances $\sigma^2$

I think my title says most of my question, but let me re-state: I am trying to simulate variable percentages (i.e., X,Y,Z) on the above simplex without using the Dirichlet distribution. The reason ...
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0answers
37 views

Statistical method to prove the influence of Random Number Generators in Evolutionary Algorithms

Evolutionary algorithms (EAs) that simulate the effects of "mutation, reproduction, selection, replacement, etc." often incorporate the use of Random Number Generators (RNGs). Different EAs were ...
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1answer
77 views

Generate random variables with predefined correlation structure AND fixing some values

I need to generate 4 random variables that show a predefined correlation structure Sigma AND where certain values of Vars 1-4 are fixed. As an illustrative example, consider the variables: ...
3
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1answer
83 views

Generate random correlated categorical variables

Lets say I want to generate 100 observations of 2 likert scaled, normally? distributed variables with 10 categories (1-10) and a pearson correlation of f.e. ~0.8. I am aware that using pearson ...
3
votes
1answer
40 views

Generating Random Zero-truncated Negative Binomial Values using Rejection Sampling

I am interested in generating zero-truncated negative binomial random variables using some sort of rejection sampling. My first thought was to simply draw from a negative binomial distribution, and ...
1
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1answer
29 views

Collective randomness of data generated using different seeds

We are generating 5 random numbers for every object we process - this is Java, but the code is pretty easy to follow (docs): ...
2
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1answer
312 views

generate a time series comprising seasonal, trend and remainder components in R

I want to generate a time series comprising three components: a seasonal component, a trend component and a remainder component. Moreover, I want to be able to chnage the level of trend, seasonality ...
0
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0answers
18 views

Synthetic Minority Oversampling with Binary Features in the data

I am planning to use SMOTE or ADASYN for creating synthetic observations for a classification problem as the data is imbalanced. The question is, there are Binary variables in the Feature set, and I ...
10
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4answers
422 views

How to generate a large full-rank random correlation matrix with some strong correlations present?

I would like to generate a random correlation matrix $\mathbf C$ of $n \times n$ size such that there are some moderately strong correlations present: square real symmetric matrix of $n \times n$ ...
0
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1answer
54 views

Randomly constructing a probability distribution for simulation

For a simulation, I want to construct the probability distribution of a random variable $X_k$ that takes only finite number of values $x_1, \cdots, x_N$. I have to assign values to each probability: ...
3
votes
1answer
88 views

References and Best practices for setting seeds in pseudo-Random Number Generation

In this document, that concerns the "set seed" command, Stata people discuss issues related to the setting of seeds when generating pseudo-random numbers. A notable "don't" is "don't use serially ...
10
votes
1answer
530 views

How to generate random points uniformly distributed in a circle?

I was attempting to simulate injection of random points within a circle, such that any part of the circle has the same probability of having a defect. I expected the count per area of the resulting ...
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2answers
541 views

Why doesn't runif generate the same result every time?

Why is it that random number generators like runif() in R don't generate the same result every time? For example: ...
4
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2answers
113 views

Generating data with a given sample covariance matrix

Given a covariance matrix $\boldsymbol \Sigma_s$, how to generate data such that it would have the sample covariance matrix $\hat{\boldsymbol \Sigma} = \boldsymbol \Sigma_s$? More generally: we are ...
0
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0answers
31 views

Random character generator: often vs. rarely occurred character rate

We need to determine if a random character generator function is BAD or not. With this random character generator, we can create lines with 8 random characters. We created statistics about the ...
6
votes
2answers
127 views

Natural example of bad results with a Lehmer Random Number Generator

I tell my students every year that there’s some correlation between successive draws in a Lehmer RNG, so they should use a Mersenne Twister or Marsaglia’s MWC256... but I am unable to provide a ...
1
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0answers
17 views

Unifirom distribution from secure random number generator?

I'm testing a Range function from big integer software libraries. The function will return an integer in the range [0,k), where ...
1
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0answers
14 views

How do i generate variables that are relevant only for some classes? [closed]

I want to generate data for classification. I've generated data with 10 variables with two are relevant for all classes and 8 noise. now, I want to generate variables that are relevant just for some ...
1
vote
1answer
552 views

R: random sampling for multivariate normal and log-normal distributions

I want to generate random monthly (m) temperature (T) and Precipitation (P) data considering that both variables are intercorrelated (rTP[m]) The tricky thing is that my random variables that have ...
4
votes
1answer
189 views

Generate pseudo-random overdispersed Poisson numbers

I have multiple sets of data which conform to overdispersed Poisson distributions which I can model with the alternative parameterization of a negative binomial distribution ($\mu$ and $D$ instead of ...
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0answers
106 views

How is the constant in Marsaglia's xorshift* RNG determined?

I get Marsaglia's basic xorshift RNG. For further randomness he suggests multiplying the result by a "suitable constant." This is some code I've found that does just that: ...
2
votes
1answer
44 views

Are all sequences of of random (uniform) numbers also uniformly distributed?

If I take some sequences of random numbers generated by a random number generator with uniform distribution, will the resulting sequences be uniformly distributed as well? By example, if I have a ...
6
votes
1answer
652 views

Generate random numbers following a distribution within an interval in R

I need to generate random numbers following Normal distribution within the interval $(a,b)$. I know the function rnorm(n,mean,sd) will generate random numbers ...
3
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3answers
166 views

Tool for generating correlated data sets

Does anyone know of a tool that I can use to generate a set of data with known correlations (and to put the icing on the cake - output this in json,csv,txt or some common format)? I am working on ...
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0answers
20 views

Generating hyperbolic variates

How do you simulate from the hyperbolic distribution? The Wikipedia article on it does not describe how to do so. I know that the hyperbolic distribution is a special case of the generalized ...