# Questions tagged [matlab]

A programming language/environment. Use this tag for any on-topic question that (a) involves MATLAB either as a critical part of the question or expected answer, & (b) is not just about how to use MATLAB .

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### in matlab, is a matrix of condition number of 1e20 definitely more ill-conditioned than a matrix of condition number of 1e19？

I am working with some ill-conditioned matrices, trying to find the relationship between the matrix's ill-conditioning and the results. However, I have noticed that the condition numbers of these ...
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### (Mixed-)model specification and comparison for testing hypotheses concerning continuous ratings

In a behavioral study following a within-subjects design, subjects of various levels of musicality (years of education) gave continuous liking ratings of three audio stimuli, each under three ...
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### Is it valid to exhaustively test all possible combinations of features to find the best combination?

I have about 1000 labelled observations from about 50 subjects responding physiologically under different situations and am trying to classify the situation (usually into three classes of roughly ...
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### How to improve prediction quality of LSTM model

I am trying to train an LSTM-based model in MATLAB to predict 365 next values given 365 previous values of a time series. Input shape is (1000, 365) and output shape is (1000, 365) i.e. there are 1000 ...
1 vote
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### How to combine confidence interval (or standard error, or standard deviation) for the sum of 2 fitted parameters

I am fitting a linear mixed model with the equation: $$y = \beta_0 + X_1 * \beta_1 + \text{random effects} + \epsilon$$ I use the model to compare difference of means between two groups, $X_1$ is a ...
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### Why does factor appear significant in 2-way ANOVA but not by inspection (mean +/- sd or error plot)?

I am puzzled about the result of a 2-way ANOVA analysis. The factors are categorical and non-random and the sum of squares used is constrained type III (the choice of categorical or SS type does not ...
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### Heteroscedastic residuals of a VECM estimated by MLE

I have estimated an VEC model in Matlab, and it turns out the residuals are heteroscedastic. Now, does anyone know how to apply HAC errors to a VEC Model in Matlab? Alternatively, given the model is ...
36 views

### Simulate bivariate bernoulli responses with predefined beta coefficients

I have a specific data matrix with features (mainly categorical). I want to simulate a multivariate bernoulli response, for example bivariate, but with a predefined vector of beta coefficients (most ...
1 vote
74 views

### Determining a mix of clusters by using naive Bayes classifiers

I have the following question which I cannot seem to find an easy answer to: given that we have two groups (let's call them 1 and 2), is it possible to determine a mixed percentage of the groups by ...
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### How do I calculate the weighted average of a 2D data set for a 3D structure?

I have a 2D data array indicating a chemical percentage content (PC) in a chemical droplet. I am trying to calculate the average PC in the droplet. The image of one of these arrays is shown below (the ...
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### Bootstrapped Confidence Intervals controlling for FWER?

I'm currently using the bootci package in MATLAB to compute bootstrapped confidence intervals. I have data for two variables and I'm interested in comparing differences in means of these variables. ...
1 vote
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### Number of simulated statistics more extreme than most extreme real data statistic

I have a distribution of $n_{obs}$ "real" data observations drawn from a normal distribution $X \sim N(\mu,\sigma^2)$, and a number $Q$ of simulated realizations of the same distribution, ...
1 vote
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### AdaBoost in Matlab - Only get 88% accuracy with Fisher's Iris data set while 100% in one layer Neural Network

I have made AdaBoost in Matlab. I get 88% in accuracy when I use Fisher's Iris flower set data. Here is the working example: ...
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1 vote
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### Creating and Using a Skewed Gaussian Distribution in Matlab [closed]

I am very new to matlab, and only used it to do some fairly basic math to visualize a method. Here is an example of what I've done with a normal distribution: ...
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### Query regarding MI and NMI in the context of image fusion

I am exploring Mutual Information (MI) and Normalized Mutual Information (NMI) in the context of image fusion. While reviewing various sources, it's often mentioned that Mutual Information's value ...
80 views

### What is the correct implementation of MCMC

I am learning Markov Chain Monte Carlo (MCMC) simulation as of the moment. My background is civil engineering and please excuse my ignorance if some of the questions are quite obvious. I want to learn ...
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1 vote
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### Is a permutation test with max statistics appropriate to account for multiple comparisons when searching for correlations between two questionnaires?

I'm trying to understand if the max statistic method for permutation test is appropriate to use and how i should apply it in my situation: I have a sample of 38 individuals who performed a task and we ...
1 vote
57 views

### Does an algorithm exist that generate copula when marginal distributions are available and stable distributed and correlation is not simple?

I have simulated data of a 4-dimensional random variable $(X_1,X_2,X_3,X_4)$. The individual pdfs of these random variables, i.e., $X_i$ where $i\in\{1,2,3,4\}$ turns out to be stable distributed with ...
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### Application of Classical Multidimensional Scaling in Matlab on new data

I would be happy if someone gives me a hint for two following questions in Machine Learning - related application of Classical Multidimensional Scaling in Matlab: 1.) It is recommended (but in my ...
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### Sample size for each trial vs Number of trials conducted for Monte Carlo Simulation

I am running some Monte Carlo Simulations on Matlab. I am wondering if running more Monte Carlo Simulation trials and taking the average value of these trials is the same as running a single trial ...
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### Chi-squared values differ heavily when calculated by hand and via MATLAB

(Question duplicated from math.stackexchange as per suggestion in the comments) In my assignment, I have to approximate a curve based on $N = 15$ data points, then test what distribution the absolute ...
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### AR And MA Order

I have a time series which has sequence as follows Upon eye balling this series , it sounds me a series which has 20 cycles where frequency/counts of event increase from 0 and then decrease after ...
1 vote
315 views

### Feature selection via RFE, MRMR, embeded methods and categorical features' impact

I am using ensemble-tree for regression (in Matlab) for my research. I have 22 features that includes 16 continuous (numerical) and 6 categorical variables. Categorical variables are based on time, ...
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