Questions tagged [simulation]
A vast area which includes generating results from computer models.
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Sample size for a vector of proportions and simulation
Currently, there are more than 10 variants of omicron virus.
Say, variant proportions are X1=0.1, X2=0.35, X3=0.15, etc. I need to calculate the number of samples needed to detect the proportion of ...
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How to guess a random walk to achieve max sample correlation?
Define this 1-D discrete random walk start from 0: roll a die (the die may or may not be fair, the fixed probability of each face is unknown to the observer/guessor)...
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Data modelling as a surface
I want to model waste generation in a city using data from the containers. I have the location and fill levels of each container over time. My idea is to use the average amount of waste in each ...
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Are the p-values obtained on the same sample using synthetic AA tests (Monte Carlo) independent values?
Let's say we have the following procedure.
We take a fixed sample of size n and perform the procedure 1000 time:
we divide (split) it equally into 2 groups;
we calculate p value using the F function (...
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Didactic example of mean-variance dependency in linear models
I'd like to illustrate the importance of accounting for the dependency between mean and variance in inference with linear models. Is my example below a good one? Do you agree with my comments on it?
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Simulation of Random Processes to Check Stationarity
I am wondering if this is a valid approach:
I want to validate that certain random processes are not weakly stationary (constant mean, covariance depends on the lag, finite variance) through ...
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I want to show by simulation that the Wilcoxon test is more robust than the Student test for non-normally distributed data
I want to test by simulation that the Wilcoxon test is more robust than the Student test for non-normally distributed data.
For example, I'm testing the ...
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Mixed model: Which parameters to provide for sample size calculations?
I am currently planning an analysis in a relatively new area of research and would like to provide data that will allow for future power analyses. Unfortunately, I am completely lost in the ...
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What is the standard deviation/uncertainty of a single observation in a meta-analysis?
I am running a simulation with parameters based on an existing random-effects meta-analysis. I would like to draw individual patients in the treatment group from a normal distribution with µ=the ...
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When can I use bootstrapping in a microsimulation model?
I'm investigating uncertainty in a linked series of microsimulation models, the outputs of each feeding into the next.
The first model (model A) generates individuals by resampling them - using a ...
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Calculating Sample Size for Cumulative Link Mixed Model (CLMM)
I am going to collect data in which each participant answers to 3 questions to 18 vignettes (each vignette has 3 questions), each question with likert scales 1-5. The dependent variables (questions) ...
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Beta-binomial relationship between dispersion and correlation parameters
Context: I have created a beta-binomial model using glmmTMB() from the glmmTMB package and I am now trying to simulate a beta-...
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How to simulate non-standardized artificial data for logistic regression?
I would like to simulate data for a logistic regression with the predictor variables on their original scale.
There are, of course, a litany of similar previous questions (e.g., here, here, and here). ...
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How can I simulate the path between two defined points but also define the overall step variance?
As stated in the question. I’m wondering if it’s possible to simulate a random walk between two fixed points (always start at A and finish at B) where the variance of the difference of steps is also ...
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Forecasting positive time series with missing values and few observations
I am working on forecasting a positive time series dataset of prices with missing values and only a limited number of observations. Specifically, I have 150 observations, one per week, and I need to ...
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