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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34 views
Kernel density estimation (CDF) with Epanechnikov kernel in Matlab
The code for Kernel density estimation was given in a recent CrossValidated question by Julio Miguel Galvez entitled "Kernel density estimation with Epanechnikov kernel in Matlab", as follows.
How ...
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27 views
Finding the parameters of bimodal and trimodal univariate distribution with MATLAB
I am rather new to Matlab and never had a lot to do with statistics, so I apologize already for possibly being ignorant of quite a bit of important knowledge. It also would be nice if you could answer ...
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0answers
30 views
How to do correlation in MATLAB
I'm trying to do correlation between two .wav files or two .pcm files using MATLAB.
I just can't figure out how to do that! If anyone can help me I would appreciate it!
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0answers
18 views
How to classify different types of fingerprints using svm two class problem in matlab?
Here I am working on fingerprint recognition. I am using SVM for fingerprint feature verification and classification. I want to classify fingerprint images using two class problem of SVM that means in ...
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3answers
66 views
Strange outcome when performing nonlinear least squares fit to a power law
I have a data set (given below in my MATLAB code) y vs. x and my eventual goal is to fit it to a power law $y=ax^b$ to see what exponent $b$ I get. I did some non-linear least squares fitting and ...
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1answer
40 views
Representing categorical data in a hybrid dataset
I'm using Matlab to discover some clusters in a dataset that has both numerical (e.g., $) and categorical (e.g.,zip code) variables. I know some tools can handle categorical variables as factors but ...
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0answers
10 views
How do I convert a dendrogram to a phytree object in Matlab? [migrated]
If I have a linkage matrix lmat and do dendrogram(lmat), I'll get a dendrogram. Is it possible to convert this to a phytree object or to obtain the newick format from it?
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34 views
Can ITML overfit?
When training using Information Theoretic Metric Learning (ITML), should I be concerned that the algorithm will overfit the data?
If yes, what is the best way to avoid it?
...
3
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1answer
171 views
What statistical test should I use?
I have 10 different biological features (for example: normal, disease 1 , disease 2, ..., disease 9). Tissue samples from various patients were imaged and 60 imaging parameters were measured. A ...
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0answers
44 views
Libsvm one-class svm: how to consider all data to be in-class
I am using Libsvm for Matlab.
I would like to construct the model for a full circumscription of all training data (in the higher SVM-space). For this I assume all my training data is correct and has ...
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0answers
27 views
Bayesian classifier for 2D coordinates (MATLAB)
I have a file in MATLAB format containing two arrays.
One array is called mat_pod (2 x 5000) in which are X and Y coordinates of every sample (vector).
The other ...
3
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1answer
44 views
Measuring Similarity of two Transient Signals
I am trying to measure the similarity between two signals, i.e. how identical they are.
A complete overlap (two lines forming a single line) should give me a value of 1, the greater the distance, ...
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1answer
19 views
Detecting and Extracting End Points of Signal in Larger Signal
I have the following time series current measurement recordings at 5,000 samples per seconds for 10 minutes:
https://docs.google.com/file/d/0ByIzsQrgb6ILakdaVVJkcEFUUGc/edit?usp=sharing
I am trying ...
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0answers
26 views
How to train SVM correctly on a 1D dataset
I am trying to use svmtrain (Statistic Toolbox) to train a linear (2 class) SVM on a 1D feature vectors. The features are not fully separable and the classes intersect.
The naive approach would be ...
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2answers
66 views
P-values from non-normal distribution
I have a collection (approximately 12,000) correlation values. Our correlation analysis does not allow for negative correlations (we correlate with sinusoidal waves, so instead of a negative ...
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0answers
45 views
Parameters estimation of ODE system
I have all the data and an ODE system of three equations which has 9 unknown coefficients (a1, a2,..., a9).
...
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0answers
41 views
GARCH models in MATLAB: Why does MATLAB force me to include ARCH terms in any GARCH model?
As far as I know, it is statistically possible/mathematically valid to fit a GARCH model to a stationary time series without including any coefficients on the innovation terms, i.e., including only ...
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2answers
74 views
How to interpret the model parameters of libsvm via MATLAB interface?
I used the MATLAB interface of libsvm for doing binary classification of 997-dimensional training data. I am trying to understand how the resulting model is used to compute the predicted output (which ...
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36 views
Mapping gini index
In my model, there are 3 players, whose income is function of two arbitrary parameters. Say, ...
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1answer
114 views
Implementing Logistic Regression in MATLAB
I have a data set of 13 attributes where some are categorical and some are continuous (can be converted to categorical). I need to use logistic regression to create a model that predicts the responses ...
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0answers
32 views
Stata - Correction for finite sample
I need to run an autoregressive model with correction for finite sample coefficients, following the model proposed by Shaman & Stine in 1989.
I usually use Stata and MATLAB for my analysis, but I ...
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0answers
18 views
Constructing a sample
I have a vector of 0's and 1's from a finite population, where there is an unequal proportion of 0's and 1's. How can I construct a sample (with replacement) from this population with an equal number ...
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0answers
86 views
Statistical test for multiple comparison with dependent observations (MATLAB)
I want to use matlab to perform a statistical test to find if there's a significantly higher mean return in any of n different sample populations. However, I can only find post hoc (although they can ...
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62 views
how to use svm classifier in feature extraction
I calculated the 5 features of a video for 40 frames
data=[eigen_x,STRAIN_ENERGY,POTENTIAL_ENERGY]
Then I run 20 videos stored the data in array form in Excel
...
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2answers
112 views
Implementation of Dirichlet cdf?
I need to compute the Dirichlet CDF, but I can only find implementations of the PDF.
Do you guys know of any library (preferably in R) implementing it?
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1answer
114 views
matlab neural network strange simulation performance
I am not quite sure if this is the right place for a question like this, but asking anyway.
Having <14x10 double> input matrix (manually normalized) and <5x10 double> output matrix (manually ...
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1answer
331 views
Cross Correlation (xcorr in MATLAB) vs Pearson Correlation (corr in MATLAB)
Are the values of xcorr(x,y) in MATLAB correlation values or not? I'm asking this because in MATLAB xcorr(x,y,'coeff') ...
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51 views
alternating least squares and all zero rows-columns
I'm trying to implement the algorithm described in Large-scale parallel collaborative filtering for the Netflix prize and I'm having some trouble understanding how to deal with a rating matrix that's ...
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0answers
49 views
trouble in prediction in neural network classifier
I am training a 4-class neural network classifier.
The details of my data are:
featurelength = 280
...
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1answer
69 views
OLS result with LASSO
I'm using the lasso function in MATLAB to perform regularized regression for parameter selection. I'm new to LASSO, so I generated some toy data and tested LASSO with lambda = 0 to make sure I would ...
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7answers
307 views
Visualizing high dimensional data
I have samples of two classes which are vectors in high dimensional space and I want to plot them in 2D or 3D.
I know about dimensionality reduction techniques, but I need a really simple and easy to ...
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1answer
60 views
Finding uncertainty in coefficients from polyfit in Matlab (no Toolboxes)
I have a data set of x- and y-values, that I want make a linear fit of. Using polyfit(x,y,1) I get the coefficients a and ...
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2answers
211 views
Finding uncertainty in coefficients from polyfit in Matlab
I have a data set of x- and y-values, that I want make a linear fit on. Using polyfit(x,y,1) I get the coefficients a and ...
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2answers
53 views
How is the signed rank statistic defined in Matlab?
Given a sequence of sample points $X_1, \dots, X_n$, I am trying to
find a Matlab function to
compute the signed rank statistic defined as $$ \sum_{i=1}^n sign(X_i) r_i $$ where $r_i$ is the rank ...
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0answers
59 views
Distribution of random variable
The chloride concentration at depth $x$ mm at time $t$ is:
$$
\text{C}(x,t)=\text{Cs}(1-\text{erf}(x/(2(D*t)^{0.5}))
$$
where $\text{Cs}$ is chloride surface concentration with Lognormal ...
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1answer
188 views
HMM forward algorithm in MATLAB
Does anyone know where can I find a pseudo code or MATLAB code of the HMM forward algorithm?
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3answers
221 views
How to test my data against an specific normal distribution?
I need to test my data to see if it follows a normal distribution with specific mean and std like N~(mu, std) I know that this can be done by Kolmogorov-Smirnov test which has a function in both ...
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1answer
35 views
Estimating point of phase transition
I have stochastic simulations that depend on a parameter $k$. As I vary $k$ the quantities I track vary gradually and then suddenly transition to very different values and continue to vary gradually ...
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1answer
350 views
PCA using princomp in MATLAB
I'm trying to do dimensionality reduction using matlab princomp, but i'm not sure i'm do it right.
here is the my code just for test, but I'm not sure that I'm doing projection right:
...
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1answer
34 views
What will be the first value when we difference for ARIMA model
I want to difference a nonstationary time series to fit an ARIMA model with X(t)=X(t)-X(t-1) formula (using diff function in MATLAB) but I can not figure out what ...
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0answers
115 views
Are GAMMs/GLM the best choice for calculating number of germs on hands?
We would like your opinion on whether GAMMs are a good option and how best to go about implementing for the following:
During a period of patient care, a nurse will accrue $Y$ colonies of bacteria on ...
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1answer
158 views
Matlab or R: relationship between categorical vs continuous variable
I have a six groups=[1:6] ACTid and a resulting continuous variable observed for each of the members is the group: Y
...
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1answer
76 views
Why sparse QR decomposition yield different results from dense QR decomposition in R?
A simple example is given below:
mat <- diag(1:6)
qr.R(qr(as(mat,"Matrix")))
qr.R(qr(dd))
the diagnal values are of opposite signs. There is a warning message ...
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1answer
122 views
What are my choices for transforming data that are not normally distributed?
I have two sets of data comparing two variables: x and y. I'd like to transform and compare both sets either in r or matlab.
...
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0answers
19 views
Comparing two or more sets of sequences
I have observed nurses during 400 episodes of care and recorded the sequence of surfaces contacts in each.
I categorised the surfaces into 5 groups 1:5 and calculated the probability density ...
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0answers
92 views
Multiple linear regression
I am new to regression analysis. Therefore, I would be grateful if you could kindly help me to set a model for my dataset. Briefly, I have images of diseased eyes (10) and control eye images (25). I ...
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0answers
33 views
PCA eigenvectors with opposite values [duplicate]
I am performing a PCA analysis in Matlab on a 110*7 dataset using some custom code. I am checking my code against Matlab's princomp and my eigenvectors are the same ...
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1answer
303 views
Kruskal-Wallis test of groups with unequal sample sizes matlab
I can't seem to work out why I can't perform a 5 grouped Kruskal-Wallis test on unequal sample sizes in matlab. Any thoughts how to do this?
Also as a post-hoc analyis using Wilcoxon Rank sum is this ...
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1answer
118 views
Metropolis-Hastings algorithm, using a proposal distribution other than a Gaussian in Matlab
I am currently working on my final year project for my mathematics degree which is based on giving an overview of the Metropolis-Hastings algorithm and some numerical examples. So far I have got some ...
3
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1answer
136 views
Two sequences, one HMM
I know how to fit a hidden markov model to a data sequence, using the matlab-implementation of the baum-welch algorithm.
But what should I do if I do not have one data sequence, but a bunch of them? ...
