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1
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2
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200
views
How to generate normal variates subject to mixed constraints?
I want to randomly generate 1000 normal variates (using rnorm, e.g.) that have mean 100. 25% of the 1000 numbers should be over 110.
How can I do this in R? …
0
votes
1
answer
131
views
Generate contingency tables with bi-variate normal distribution
I want to generate r x c contingency tables using Bi-variate normal distribution. Most of the works deals with generating tables from multinomial distribution where the total frequency is fixed. … Suppose if i want to generate r x c tables from Bi-variate normal, Is it necessary that r and c should be equal? If so, How to generate as contingency tables using R? …
1
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1
answer
193
views
Can/should one generate Ginibre ensembles of random matrices using low-discrepancy normal va...
Each matrix ($\rho_{\frac{1}{2}}$ in the notation of the first ref.) requires 64 random unit normal variates for its generation. … Should I be able to speed convergence by using low-discrepancy series of normal variates, and if so how might that be effectively accomplished? …
1
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0
answers
36
views
Generability of log normal distributed variates
If I simulate the generation of measurements from a number of batches each sampled from log normal distribution but with varying parameters the complete ensemble again comes out log normal. … But can I know just from finding that the total of measurements is log normal that the individual batches also are this way? …
1
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1
answer
93
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Generate a syntetic log-normal two dimensional random field
In order to do that, I would like to generate a synthetic log-normal 2D random field.
The idea is to extract from it some points with their two dimensional coordinates and (of course) their values. … I do not think that is enough to compute a bi-variate log-normal distribution. Am I right? …
2
votes
Accepted
How to interpret multiple calls of rnorm() function in R?
This question is really about R syntax and not about the normal distribution or sampling. So I guess it's
'off topic' here, and may be closed.
I'm not quite sure what your difficulty is. … If you set the same seed before each program,
then you should fill an $n\times p$ matrix
by columns with exactly the same normal variates.
n=5; p=2
set.seed(713) # set seed
X = matrix(rnorm( …
6
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2
answers
2k
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Sampling from matrix-variate normal distribution with singular covariances? [duplicate]
The matrix-variate normal distribution can be sampled indirectly by utilizing the Cholesky decomposition of two positive definite covariance matrices. … Is it possible to adapt the SVD based sampling technique for the multivariate normal case that overcomes this difficulty to the matrix-variate case? …
4
votes
Accepted
Mean and variance of a normally distributed random number created from the average of a set ...
FYI, there are much better ways to generate normal variates that do not require inversion of the normal CDF, such as the polar method. …
1
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0
answers
67
views
Approximating a distribution with normal
I want to approximate this distirbution with a multi-variate normal. …
1
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2
answers
514
views
Probability distribution for proportions
When I plot historic data of productivity it suggest a Normal Distribution, however if I generate a normal random variate I will occasionally obtain negatives or even productivity values over one. … Can I use a Normal distribution -and implement some mechanism for invalid values- or there are more suitable distributions for proportion data? …
4
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1
answer
207
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Generate nonnegative variates with mean 1 and specified variance-covariance
In the applications I have in mind (described below), typically the diagonal of $\Sigma$ has a few entries which are $1$ or even as large as $1.5$, so a multivariate Normal will easily generate negative … This R package vignette describes the generation of replicate weights for the "generalized survey bootstrap", and describes how multivariate normal distributions are used to generate replicate weights …
2
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Log-normal mean and standard deviation change after sampling
As a rule, I do not use any platform's method to generate lognormal variates, because the conventions about specifying parameters are so varied and confusing. … I always generate normal variates and exponentiate them, because then I know what I'm getting.)
import numpy as np
from statistics import mean
from scipy.stats import norm
N = 1000000
m = 1.75917e-7 …
2
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3
answers
324
views
Generating random nos based on 'k' moments
How do I generate random nos based on say k moments? (no other constraints on support)
When k = 2, we generate random nos. from a normal distribution defined by the 2 moments. … I have a uni variate sample and no more information about anything. Now, I want to try and simulate nos. from the distribution from which this sample was drawn. …
4
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1
answer
718
views
Irwin-Hall distribution scaling
From https://en.wikipedia.org/wiki/Irwin–Hall_distribution:
The generation of pseudo-random numbers having an approximately normal distribution is sometimes accomplished by computing the sum of a number … How would you rescale, and what does “variate” mean here? A normal distribution has infinite support (theoretically if not practically) so it does not seem possible to rescale easily? …
1
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Accepted
How to convert a Johnson normalized variable back to a marginal variable
You:
Generate an iid uniform time-series
Pretend it's Johnson-distributed
Apply a transform that converts Johnson variates to standard normal variates, and does who-knows-what to your uniform variates … Fit an arima model to your (IID) data
Simulate from an arima with the fitted parameters using normal errors (You didn't change the rand.gen arg in arima.sim; it defaults to standard normal.) …