# All Questions

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### Would PCA work for boolean data types?

I want to reduce the dimensionality of higher order systems based and capture most of the covariance on a preferably 2 dimensional or 1 dimensional field. I understand this can be done via principal ...
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### Dummy coding , Effects coding , is there somthing called "Averaging coding or mean coding in Regression model?

When we perform a regression analysis with categorical predictors, we can use (1, 0) " Dummy coding ", the coefficients in this case represent the deviation of the groups' means from the mean of ...
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### GAM : choosing the a function for each predictor

When using GAM methods for prediction: y = af(x1) + bf(x2) + cf(x3)... Where x1,x2.. are predictors / features used in the data. The gam package in R helps us find the best functions and the ...
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### explanation of MCMC and bayesian estimation

I have some questions about bayesian methods. First of all I have a set of iid observations, calling $y_1,\ldots,y_n$ that come from a certain distribution $f$ with unknown parameters(for example ...
70 views

### Mixing probabilities in mixture models using EM

Assume we want to estimate the mixing probabilities ($\pi_{k}$) for each member distribution in the mixture model. We know that $\sum_{m}^{K}\pi_{m}=1$, so we can formulate the optimization problem ...
12 views

### Goodness of fit in R

I need to check for goodness of fit using K-S test in R. I have a dataset (containing 50 data points) and a non-standard continuous probability distribution. Should I peform a one-sample or two-sample ...
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### Kernel methods in machine learning?

I am beginning to tackle geostatistics problems where I tried to apply kriging(gaussian processes) to interpolate demographical water drop. According to my understanding, kernel methods are something ...
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### Is there are better way of solving this problem than using a Neural Network Regression Model?

I'm working on power plant time series data from a SO2 absorption process and my main objective is finding out which independent variables are critical for reducing SAG (% of SO2 concentration ...
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### Seemingly unrelated bivariate probit for endogeneity: interpretation of Rho

I would like to estimate the effect of health insurance coverage on type of healthcare provider chosen--either public or private--at last illness using a nationally representative sample of people in ...
9 views

### Random Variable Decomposition Standard Error

I have a decomposed random variable $X$ into partitions $A_1,A_2,\dots A_m$. I know how to compute the expected value of X and the variance of X given the variance and the standard errors of $X$ ...
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### Poisson vs. Gaussian in Geomagnetic Data

I've been studying geomagnetic signals using a threshold approach to detect pulse events in the data. The question here is what is the significance of the crossover of stddev and mean as the ...
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+50

### Help in understanding a paper on how to apply Bayesian estimation in $R^k$ Euclidean space?

I am facing difficulty in identifying how the formula given by Eq(2) in the paper ...
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### How to deal with an aliased predicator in a generalized linear model?

I am running a GLM model with a binomial distribution and a logit link function. The dependant variable is the number of changes in agricultural practices in a given households during the past 10 ...
457 views

### Log-likelihood ratio in document summarization

I initially asked this on stack overflow and was referred to this site, so here goes: I am implementing some unsupervised methods of content-selection/extraction based document summarization and I'm ...
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### Difficulties obtaining valid predictions when using interactions

I examine long term trends (2003 to 2014) for a continuous dependent variable. I want to predict the mean each year in relation to income category. Income is arranged in quintiles, from 1 (poorest) to ...
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### repeated measures threeway linear mixed model

I'm new to using R, only started in the last 2 weeks so I apologize if I'm missing something very obvious. I am analyzing data from a repeated measures experiment with three factors, diversity (2 ...
9 views

### Noisy data in classifiers

I have a data set which has three classes(Labelled 1,2 and 3).However ,there is also noise in it. Should I classify with noise,so I will assign one more label to it (label 4) OR should I remove it ...
30 views

### Gaussian Process Regression for piecewise linear response functions

I am performing Gaussian Process Regression (without noise) for response functions which are piecewise linear. My question: Does there exist a covariance function, such that sample paths from a ...
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### Back end processing of Pattern Matrix during EFA.

I want to know that how pattern matrix (using maximum likelihood and varimax rotation) is calculated. What is the underlying formula or pattern that displays such results? Please guide.