Questions tagged [monte-carlo]
Using (pseudo-)random numbers and the Law of Large Numbers to simulate the random behavior of a real system.
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Sampling from sample (and not from population, and not from distribution)
Say I have a large model with input parameters that are themselves the result of large models that are long to run. I am interested in the uncertainty of the large model results, and want to estimate ...
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16 views
Convergence Proof of First Visit Monte Carlo Control
I am currently trying to find a formal proof of convergence for the Monte Carlo Reinforcement Learning Methods described in Sutton,Barto's Book "Reinforcement Learning - An Introduction" , Section 5.
...
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14 views
Stopping rule in a Monte Carlo simulation for a convergent sequence of unknown random variables
Given an unknown random variable $X: \Omega \mapsto [a,b] \subset \mathbb{R}$, let us imagine we want to estimate $\mathbb{E}(X)$. We can sample sequentially as many times as desired, let us say $m$ ...
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1answer
22 views
Proper way to generate random seeds for Montecarlo runs [closed]
I am running a SIMULINK model which has noise additions. At this moment we have a variable called seed which is initialized at zero.
seed = 0;
Then for every ...
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8 views
Determine confidence in estimate from past estimates
I have a population on the order of 10,000 samples. These samples represent individual estimates of a variable, and for each estimate I also have the actual value of the variable. For each sample I ...
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9 views
How to check if a sequence's subsequences (trigrams) are random using a Monte Carlo experiment?
Let's say I have a process that produces sequences.
I might have another process (or processes) that will add their own output to the data sequences at random points.
To check if a subsequence (any ...
3
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2answers
110 views
Importance sampling estimation of power function
Problem
Suppose we are given $\text{Poisson}(\theta)$ model, and the null hypothesis is as follows:
$$
H_0 : \theta = 0.1 \ \ \text{vs}. \ \ H_1 : \theta < 0.1
$$
Suppose we take sample of $n=...
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1answer
26 views
Deriving mu and sigma from the log normal distribution given the expected mean and variance?
I'm attempting to sample from the log normal distribution using numbers.js.
Looking at Wikipedia it looks like I need to solve for mu and sigma. So if I want the mean of the samples to be 10 then I ...
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29 views
Symmetric decomposition of a covariance matrix that is not given explicitly
I am implementing a Monte-Carlo method that requires decomposition of a $k
\times k$ covariance matrix $\Sigma=A^TA$ where the dimensionality of $A$ should also be $k\times k$. No further constraints ...
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1answer
78 views
Estimating When A Time Series with Random Spikes Crosses a Threshold for the First Time
tl;dr Is there a way to estimate when a random spike in a time series would cross a threshold for the first time?
The following is data of my performance in the game Super Hexagon, whose goal is to ...
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24 views
Numerically calculating the integral of the discrepancy between the empirical and theoretical distribution functions
Having a sample of observations, $x_i, i=1,..,n$, to test the null hypothesis stating that the data follows a specific distribution
$F_0 (x)$, the Cram\'{e}r-von-Mises goodness-of-fit test statistic ...
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1answer
17 views
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1answer
39 views
Monte Carlo test for statistical significance of typhoon passage frequency
This question is related to this post: https://stackoverflow.com/q/56288002/6638232
Basically, I am trying to perform a significance test using Monte Carlo simulation but I am having a problem in ...
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0answers
14 views
Computing slope of data with correlated errors using Monte Carlo method
I have $N$ pairs of $(x,y)$ measurements. I have the (estimated) uncertainty of each $y$ value as well as the correlations between each pair of $y$ values.
I want to know whether there is a ...
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0answers
26 views
Literature on design of importance sampling distribution using MLE or point-estimates of highest modes
Suppose I have many distributions $p_i(\theta)$ I wish to take expectations over $$\mathbb{E}_{p_i}[\mathbf{f}_i(\theta)]$$ where the $\mathbf{f}_i$ are vector-valued. In my problem the $p_i$ share ...
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0answers
11 views
sample size to detect variability in a sample
I have a sample of continuous data which I use to build a random forest model. Now I want to determine, how many additional samples I would need to improve the prediction (reduce the RMSE by a certain ...
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2answers
142 views
How do Bayesians verify their methods using Monte Carlo simulation methods?
Background: I have a PhD in social psychology, where theoretical statistics and math were barely covered in my quantitative coursework. Through undergrad and grad school, I was taught (much like many ...
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1answer
50 views
Metropolis-Hastings - interpreting the transition kernel: alpha*proposal
I thought I had great intuition and mathematical understanding of the Metropolis-Hastings algorithm, until closer inspection... as I started compiling my notes, I realized I do not understand the ...
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5 views
Generate scenarios of multiple related parameters
Assume I have three industry datasets: interest rates, inflation and unemployment. Data contains information of last ten years and it's monthly.
Now, I would like to create N possible scenarios of ...
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34 views
error of Monte Carlo estimate of root mean square speed (vrms) of ideal gas
I am trying to use Monte Carlo method to estimate the oot mean square speed (vrms) of an ideal gas, the speed of an ideal gas follows the Maxwell-Boltzmann distribution:
$$p(v)= \frac{4}{\sqrt {\pi}}(...
2
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1answer
110 views
sequential Monte Carlo sampler, why the extended space and backward kernel?
Hello cross validated,
I am currently studying sequential Monte Carlo samplers.
My current understanding is as follows:
We are interested in the marginal distribution of some sequence of joint ...
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1answer
39 views
Proving the Accepted Samples from Rejection Sampling follows our Posterior Distribution
I get confused how the author gets to line $(1)$ using the indicator functions. If someone can explain this to me or give me a hint that would be greatly appreciated. Thanks!
Define the following:
...
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15 views
Cholesky decomposition in control variates method (Monte Carlo variance reduction technique)
The control variates method, used as a variance reduction technique for Monte Carlo simulations, takes one new variable $t$, correlated to the random variable $m$ to estimate (using the same notations ...
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16 views
True covariance matrix in Monte Carlo simulation?
In a linear model, such that Population model is
$y_{it}=\ {\beta_{i1}f}_1+{\beta_{i2}f}_2+\cdots{\beta_{ik}f}_k\ +\ \varepsilon_{it} , i = 1,2,3...,p$ and $t=1,2,3,...T$
and
$\mathrm{\Sigma_y}\ =\ ...
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2answers
57 views
How do we reuse and store the output of an MCMC?
For many Bayesian models, the posterior distribution is intractable... a solution is then to sample points from this unknow distribution with a Markov Chain Monte Carlo (MCMC). But at the end, how do ...
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11 views
Monte Carlo Simulation (or bootstrapping ) mutually exclusive events
Say event A probability of happening in a day is 1%; event B probability of happening in a day is 5%. Assuming they are independent, if I want to build a simulation model to simulate 1000 days, and ...
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41 views
Population Monte Carlo Algorithm using L2 Distance Measure/ Likelihood Distribution
I am currently struggling with some concepts of the Population Monte Carlo Framework. Initially, I came across this set of algorithms as I am currently trying to infer parameters from a 7D ...
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1answer
25 views
MCMC changing multiple parameters
What is the standard way of drawing multiple parameters for a MCMC run? Say I have 9 parameters, what is the most efficient method to get all parameters to explore their distributions properly?
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0answers
17 views
Error bars of Monte Carlo expectation with correlated samples
I will try to phrase the question in a general way, then give my specific case as an example.
Suppose I want to evaluate $Q = \mathbb E \left[ f\left(X, Y \right) \right]$ where $X$ and $Y$ are ...
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1answer
69 views
INAR(1) simulation in R [closed]
How do we simulate values of $Y_t$ for a maximum value of $t=60$ when we have an INAR(1) process as follows:
$Y_t=ρ^*Y_{(t-1)}+R_t$
where $t$ takes values from 1 to 60, $ρ=0.3,0.8$, $ρ^*$ is ...
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25 views
Simulation in Stata: instrumental variables with endogenous nonlinear regressor
I'm doing an exercise from Microeconometrics Using Stata, by Cameron and Trivedi, Exercise 11 of Chapter 6 (page 204).
"When an endogenous variable enters the regression nonlinearly, the obvious IV ...
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1answer
14 views
Direct/indirect sampling of conditionals in Gibbs sampling
I have some problems understanding the definition of Gibbs sampling.
Let us take into consideration a bivariate distribution
\begin{equation}
\pi(x_1,x_2): S \subset \mathcal{R^2} \rightarrow \...
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32 views
Calculating empirical p-value for Anderson-Darling test
I have the data $x_1,\ldots,x_n$. First, I fit the stable distribution to this data and obtain a vector of estimated parameters $\hat{\theta}$. Now, I want to use Anderson-Darling test for stable ...
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24 views
Monte Carlo integration for Bayesian parameter estimation
I want to determine the credible interval of a quantity $\theta_1$. I want to make this estimate using observed data by assuming a certain model which depends on $\theta_1$ as well as about n=15 ...
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23 views
MCMC chains and Convergence
This may be a dumb question to ask, but I was doing MCMC sampling of my parameters $\alpha_1, \ \alpha_2 .... \alpha_{50}$, where $\alpha_i$ denotes for the same parameter $\alpha$ at the time i.
I ...
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1answer
40 views
Monte Carlo Drawing Balls Probability Question in R [closed]
Disclaimer: I'm very new to functions in R and really to coding in general.
I'm trying to answer the following question using a simple Monte Carlo sampling procedure in R: An urn contains 10 balls. ...
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1answer
62 views
Monte Carlo Sim for Coin Toss in R
I'm trying to answer the following simple probability question but using a monte carlo type simulation function in R: A fair coin is flipped 100 times. Find the probability that the number of times it ...
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1answer
30 views
likelihood of latent state space model
Im trying to calculate the likelihood function of my latent state space model.
My model has Poisson observations
$p(y_t|\beta_t;x_t) \sim \mathcal{Poiss}(z)$.
where $z$ is the rate of the poisson ...
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1answer
33 views
How to simulate sample proportions near or at zero in a Monte Carlo simulation?
I am running a chain of Monte Carlo simulations to estimate uncertainty in some model estimates (which are derived from a series of estimates). An important variables used in one of the steps is a ...
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6 views
Parallelizing Rollout/Simulation phase of Monte Carlo Tree Search
I have a Monte Carlo Tree Search implementation that I need to optimize. So I thought about parallelizing the rollout phase.
How to do that? Are there any python modules etc that you would recommend?
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1answer
43 views
Books for self-learning about statistic Simulation?
Preferably an introductory book, i.e. for undergrad (or notes or something like that) that explains concepts with detail and with lots of examples, without losing the formality.
That covers the ...
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0answers
44 views
Lottery with known EV and standard deviation. Probablity of positive ROI after x trials?
Lottery with the following payout table:
**Payout** **Frequency**
0x 0.59992
1x 0.34992
5x 0.04982
1000x 0.00035
...
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0answers
35 views
Feature Selection using Monte Carlo Tree Search
Trying to tackle the problem of feature selection as an RL problem inspired by this paper here: https://hal.inria.fr/inria-00484049/document
So I used Monte-Carlo Tree search for this problem, where ...
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1answer
30 views
How to Show that a Distribution is a Stationary Distribution for Metropolis-Hastings? [closed]
For an Ising Model with a (2L+ 1) by (2L+ 1) square grid
of magnetic particles, show that $$\pi(\xi)=\frac{1}{Z_\beta}e^{\beta\sum_{x,y=x}{\xi_x\xi_y}}$$ Is indeed a stationary distribution for the ...
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20 views
Creating a monte carlo simulation?
I am given two columns of data that are normally distributed with a mean of zero and I need two do a t-test for a random sample of 20 pairs. What I am confused about is where does the sample come from....
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1answer
372 views
Variance of Monte Carlo integration with importance sampling
I am following these lecture slides on Monte Carlo integration with importance sampling. I am just implementing a very simple example: $\int_{0}^{1} e^{x}dx$. For the importance sampling version, I ...
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2answers
76 views
Expected outcome of a process following a uniform distribution [closed]
A gambler is playing a game of roulette. There are $37$ possible outcomes, each numbered from $1$ to $37$. The probability of rolling any outcome is the same for each outcome. One game of this ...
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29 views
Use Monte Carlo methods to approximate the probability that a line joining 2 random points in a ring 1 < x 2 + y 2 < 4 does not cross the inner circle
My method so far is to fix one point (polar coordinates (r,0)) and then generate a large number of points (polar coordinates (r,a))) in the ring and accept these points if their angle 'a' satisfies ...
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57 views
Chi Square and Fisher’s exact test with Monte Carlo
SPSS can’t calculate Exact test for 4x7 table of my data so I did it with Monte Carlo. The output is given below.
Considering the rules of Chi-square, I should use Fisher’s $p$-value for the result of ...
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1answer
70 views
MCMC - target distribution, proposal distribution and likelihood function?
i have just started out in MCMC and I am not sure if I fully understand the concepts of MCMC with respect to the above terms. Let me try to explain that in my own words and include some thoughts / ...
