# Tagged Questions

For questions about how to parameterize some statistical model, or comparisons between different ways to parameterize.

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### Estimate parameters for skew normal distribution

I know there is already at least one question answer with this, but I think the solution does not apply in my case. I have a population for which I know the mean, variance and skewness. I saw how to ...
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### Using lasso regression in Matlab with constraints on lambda values

I have successfully ran a lasso regression on Matlab, however, some of the lambda values result in a non-steady state solutions for my linear problem. I would like to basically force the regression to ...
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### What are the model parameters and hyperparameters of Random Forest classifier?

The parameters required for a Random Forest classifier are as follows: Depth, $d$ No. of random features, $K$ No. of trees, $I$ Randomizer seed, $R$ Which of the above are hyperparameters and ...
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### What is a parameter in Bayesian analysis?

In any case study, when we use Bayesian analysis to solve our problem we consider a model parameter which is sometimes known and sometimes unknown. And using this parameter(and of course prior data) ...
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### Support of distribution (distribution fitting)

This might be a weird question. I want to know why Matlab still run to produce estimated parameter whenever I input data which doesn't belong to the support of the distribution? E.g. I want to ...
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### Splitting of parameter space when using random mutation hill climbing

I have developed an agent-based model in NetLogo, and to calibrate the model and its parameters I want to use the random mutation hill climbing method. However, since my model is computationally ...
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### Choosing the good initial value of the Newton-Raphson iteration method for Maximum Likelihood Estimation

I want to estimate the four parameters of Exponentiated Modified Weibull Extension (EMWE) distribution introduced by Sarhan and Apaloo (2013) with the Maximum Likelihood Estimation. Because the first ...
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### Improving convergence of simulated annealing

I have a complex curve that I need to approximate with a parametric model (5 parameters). The parametric model itself is highly non-linear, and small changes in parameters can lead to big changes in ...
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### Justification of simulated annealing versus random search

I have a set of 16 integer parameters to optimize. The parameter space is too big for an exhaustive search, so I am using simulated annealing instead. I think my simulated annealing works - it finds ...
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### Hierarchical Weibull model: choice of parameterization

I am experimenting with fitting a Bayesian hierarchical model using right-censored and Weibull distributed time-to-first-event data. However, I have some issues that might be related to the Weibull-...
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### Help: Random Forest optimization (image classification)

I'm having trouble classifying images using a random forest. The images all have a very similar scale, but they may be rotated arbitrarily around a fixed point in the image. The core problem is ...
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### Completely understanding the Confidence Interval - how is it not a probability of containing a population parameter?

I've been doing data analysis for a while, but recently I questioned my understanding of the oft-misunderstood confidence interval. So, I read multiple sources. Many of them say explicitly that the ...
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### Estimating a Mixture Model from incomplete datasets

I would like to figure out the best way to estimate a univariate mixture model from an incomplete dataset. For example, generate a mixture of two normal distributions and then crop the dataset below ...
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### what is the relationship between covariance matrix and its variance parameter in linear mixed model

In parameter estimation for linear mixed model for unknown variance, I met some statements saying that "we assume G (as variance) is only known up to its variance ...
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### Get level set from 3D dataset obtained exploring a 2D space parameter

I am exploring a 2 parameter space performing simulations. As a result I get a surface as a function of these 2 parameters. I know this is probably simple but I don't know how to look for it. Now I ...
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### estimating correlation of estimated parameter from windows

Say you have a process $x[n]$ for which you estimate a parameter $\theta$. You want to know how stationary is the parameter $\theta$ over time. So, you take $x[n]$ and divide it to windows of duration ...
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### Questions Regarding Item Response Models – the 3PL model vs. the mixture of 2PL and 3PL model

I currently work on an item analysis for an assessment. The assessment consists of 25 multiple-choice questions. Each question has 4 choices with one correct answer. I used different IRT models to ...