MATLAB is a high-level language and interactive programming environment developed by MathWorks. It is the foundation for a number of other tools related to statistical analysis, including Statistics Toolbox, Optimization Toolbox, Curve Fitting Toolbox and Neural Network Toolbox.

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Correlation between ordinal variables

I want to know the correlations between 3 groups of variables which are ordinal (rating of 1 to 10). I have followed the formula on wiki and computed the Kendall tau-b correlation coefficients matrix. ...
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1answer
16 views

Matlab's sizing of exogenous inputs to vector time series

Matlabs commands for analyzing vector time series (e.g., vgxvarx, vgxproc) accept exogenous inputs. I understand the explanation that each of p inputs can have q paths with r observations, requiring ...
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17 views

How to use Kernel Regression to predict new data?

I have climate data for 240 predictors and precipitation flux (as the target variable) for 3000+ days. I want to use Gaussian kernel regression to predict the precipitation flux for the next 2000+ ...
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22 views

Which normalization procedure is suitable for Principal Component Analysis (PCA)? [on hold]

I have a data-set that has features with different ranges, scales and measurement units so as proposed in literature I'm using Principal Component Analysis (PCA) with "correlation matrix". In this ...
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6 views
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20 views

Maximum Likelihood Algorithm Implementation [on hold]

Hello Guys i have to implement Algorithm of Maximum Likelihood using Hyper-spectral data of 170 bands, have to classify 16 classes using ground truth data. The formula for implementation is as follow, ...
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1answer
29 views

Hazard function of a gamma distribution

The system we are working on is biological, more specifically the distribution of specific events across a chromosome. This can be thought of as 1D array (the chromosome) across which points can be ...
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1answer
30 views

What are variable weights in principal component analysis (PCA) using MATLAB?

Can I set variable (inputs) weights in MATLAB for principal component analysis using pca() function? There is VariableWeights ...
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0answers
22 views

[CNN]: Predict label of one single image using DeepLearnToolbox [on hold]

I am using DeepLearnToolbox to do CNN (Convolutional Neural Networks). I have computed my network successfully and I've seen my accuracy, but my question is: How can I query one single image into ...
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5 views

How to load new data into ntstool in matlab? [on hold]

I am using neural network for time series prediction using ntstool in matlab. But in the tool ,there is an option to load data set from the examples. How to load my data set into the tool? Please help ...
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1answer
58 views

Most accepted theory to analyse trend in data series

I have pollutant concentration for long period I want to determine trend. I have read some of the question answers in this blog regarding same . I have few queries. What is most accepted theory to ...
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0answers
14 views

SVM always predicts same label

I have 11 labels. I trained an SVM model: ...
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1answer
39 views

What is the meaning characterizing a model as “conditional mean”

I've been going through time series material of late, trying to re-invent myself as a practitioner in the field. Until I got to the point of actually trying to Matlab some models, I had never run ...
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26 views

Make 2D color histogram with uniform distribution (Likert scale)

UPDATE: I've been told that I cannot specifically ask for help in regards to the programming (MatLab and PR Tools), but instead should seek help for general techniques. So that's what I'm doing. Long ...
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1answer
26 views

How do I obtain the “Anomaly series” of a time series?

I have a time series of the Sea Surface Temperature (SST) of the Caribean Sea and I have to obtain the anomalies of that time series. ...
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1answer
38 views

Time Series Analysis using Fourier Technique

i need to perform "Time Series Analysis" using Fourier Analysis/Technique on temperature data of 17 years. Their are four columns in it "Years", "Months", "Days" and "Temperature in C". I need basic ...
7
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1answer
122 views

Mechanics behind deviation from random distribution

The system we are working on is biological, more specifically the distribution of programmed DNA damage events across a chromosome. This can be thought of as 1D array (the chromosome) across which ...
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0answers
10 views

Why are parameters in output of my support vector regression going to zero? [migrated]

I am trying to predict next value in a time series from epsilon-support vector regression using libsvm library in matlab.Following is my code. From an excel file, I am taking first 3500 samples for ...
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0answers
23 views

how to do a t-test in matlab of 2 data(matrix of 3 ex: 180*820*23) [closed]

how to do a t-test in matlab of 2 data(X and Y) and X and Y have each 9 signals those signals are matrix of 3 ex: 180*820*23 or 180*820*30 etc..) and which i have to take the peak from each signal, so ...
10
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1answer
142 views

Distribution of p-values - Binomial test

I heard that under the null hypothesis the p-value distribution should be uniform. However, simulations of binomial test in MATLAB return very different-from-uniform distributions with mean larger ...
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20 views

MATLAB: prediction bounds and constrained linear/nonlinear regression

I'm struggling to fit the following rational function to data $(x_i,y_i)$: $$\hat{f} (x) = \frac{1+p_1x+p_2x^2}{1+q_1x+(p_1+p_2-q_1)x^2}$$ The reason why I chose this model is a long story. Let's ...
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0answers
9 views

Why am I getting an empty matrix from svmpredict? [migrated]

I want to make predictions from a simple time series. The observations y=[11,22,33,44,55,66,77,88,99,110] and at time ...
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0answers
7 views

Sparse random matrix in Matlab with values in different range than [0,1] [migrated]

How do I create a sparse random matrix in Matlab with a value range different from the default [0,1], say [-1,1]? Two things ...
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1answer
30 views

Matlab's VARMAX regression parameters/coefficients nX & b

I'm having a bit of trouble following the explanation of the parameters for vgxset. Being new to the field of time-series is probably part of my problem. The vgxset help page ...
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2answers
51 views

Simple way for histograms Clustering

I'm trying to cluster set of histograms. The histograms represent the frequencies of the distribution for a numbers from 1 to 5. The following figure shows two samples of my data. I have 10,000 ...
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0answers
24 views

Choosing start points for fitting of single and double Gaussian to experimental data

I'm interested in fitting a single and double Gaussian models to some experimental data in matlab. I want to use the amplitude coefficient to detect decreases in the data. I know that the goodness of ...
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0answers
23 views

Correlating two time series with delay and non-periodic sampling times

I am trying to analyze some data using Matlab. There are two datasets sampled by different sources over time (no fixed sampling frequency). After reading the data I perform a linear interpolation of ...
2
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1answer
83 views

data and curve fitting

I have several datasets that I need to be able to fit (the goal is to find the outliers). The datasets were created by groups of images and the x is an index number of the image and y is a focus ...
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1answer
9 views

GPML producing wrong output using correct target labels

I am using the GPML code found here. The key function in the aforementioned library is the gp function described below: Two modes are possible: training or ...
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0answers
26 views

how can i find confusion matrix of svm classifier on MATLAB to classify into 4 types of HEART beat

i want to find confusion matrix of svm classifier. i am work on ECG signal to classify 4 types of arrhythmia using svm on MATLAB..i have write code for this but something is wrong plzz help me to find ...
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0answers
18 views

How to perform F-test significance testing in Matlab?

I have two quantities in Matlab say T1 (1x44100 array) and T2 (1x44100 array). I have calculated their ratio ...
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2answers
49 views

F-distribution of data in Matlab

I have F = 1x44100 vector in Matlab. Based on how this was calculated, we have predicted that this fits the F-distribution with 16 degrees of freedom for both numerator and denominator. I am really ...
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0answers
42 views

Method to minimize a quadratic form

How should I minimize a quadratic form $g(x)^TA(x)^{-1}g(x)$ with respect to $x$, where $g$ is a vector which depends on the vector $x$? This quadratic form is obtained from a quasi likelihood ...
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0answers
37 views

Plot eigenvectors on scatter plot

I have a problem and need some assistance. I have a scatter plot of two variables $x, y$, and I want to plot the eigenvectors on it. I tried one methods plotting each eigenvector as a line equation ...
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15 views

What do performance and gradient parameter signify in nntraintool progress?

I am using Pattern Recognition Tool for Image Classification. nntraintool uses trainscg algorithm. I am not able to understand the parameter values displayed under progress bar. Attaching the same. ...
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1answer
51 views

Training an SVM and performing cross validation

I am training an SVM and I have 40k Negative Samples and 17k Positive samples. What I did is that I have divided my samples into training and testing subsets. In order to train the SVM I have used ...
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36 views

Difference between regression and performance plot of Artificial neural network in MATLAB

I am having problem understanding regression and performance plots of ANN. My data consists of 13 inputs and 3 outputs. Parameters used for simulation can be found here. The problem I am facing is ...
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1answer
54 views

Logistic Regresion / SVM / Random Forest Implementation in Matlab

I would like to implement (L2-regularized) Logistic Regression, (L2 regularized) SVM and Random Forest for multiclass classification in Matlab (without using a toolbox or the corresponding functions ...
1
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1answer
39 views

Why does the amplitude, bandwidth and position of Gaussian change when data changes from positive to negative

I'm trying to fit a single Gaussian to some values in Matlab. When the values are positive, the model fits without any issues. However, when these values become negative, the r squared value changes, ...
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3answers
131 views

How to interpret this autocorrelogram graph?

I am new to statistics. I found a script which makes a autocorrelogram graph(see attached) of spike timings of a neuron. I got the graph but I am not able to interpret it. Matlab Code below. ...
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49 views

Residuals - What are they? How can i obtain them?

So, i have a data set. I decide to fit an AR(1) model to it thus obtaining a model of the form $X_t - \hat{\phi} X_{t-1} = Z_t \quad Z_t$ is $WN(0,\hat{\sigma^2})$ Which in matlab is given by ...
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1answer
80 views

Confidence Interval Calculation

I have temperature data of July 1991 to 2007, and wants to find the Confidence Interval at 95%, which distribution is best fit the data, Z or T. Please give me reason also. minTemp = 14.4444, ...
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0answers
22 views

Confidence Interval Calculation [duplicate]

I have temperature data of July 1991 to 2007, and wants to find the Confidence Interval at 95%, which distribution is best fit the data, Z or T. Please give me reason also. Thanks
2
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1answer
88 views

Combining multiple features in a classification task

This question is a little general, but I am looking for suggestions of a method. I have several images that contain images of animals and I have to characterize which animals they are, let's call them ...
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1answer
56 views

Ryan-Joiner test for normality in MATLAB

I have been reading a comparison of Anderson-Darling, Ryan-Joiner and Kolmogorov-Smirnov tests at this link. While I can find functions for A-D and K-S (one-sample) tests in MATLAB, I am not sure if ...
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24 views

An Algorithm for Maximal Correlation

Given a pair of random variables $(X,Y)$ over a product space $\mathcal{X}\times \mathcal{Y}$, the maximal correlation coefficient is defined as ...
2
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1answer
56 views

Is PCA still done via the eigendecomposition of the covariance matrix when dimensionality is larger than the number of observations?

Disclaimer: I understand that this question has been answered on CV, but I am asking about the particular implementation, which AFAIK, is not answered yet. I have a $20\times100$ matrix $X$, ...
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0answers
8 views

What Matlab optimization solver gives you the t-stats and p-value for the estimates? [duplicate]

I calculate a data log likelihood (evaluated at a set of parameters to be estimated), and my task is to find the set of parameters that maximize my log likelihood. My problem is: thought there are a ...
1
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3answers
72 views

How to use an optimization solver to get t-stats and p-values for the estimates?

I calculate a data log likelihood (evaluated at a set of parameters to be estimated), and my task is to find the set of parameters that maximize my log likelihood. My problem is: thought there are a ...
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0answers
18 views

Is there any reason that cross correlation would perform well or poorly on sparse binary arrays?

I am using matlabs xcorr to correlate simulated photon count data that has some Gaussian random noise set on top of it and it is working fine when the average value in the arrays is greater than one ...