# All Questions

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### Cross spectrum problem

I'm looking for some advice to find the cross-spectrum for this system. $$y_t= r_t+\epsilon_t$$ $$r_t=\frac{\theta}{1-\psi z^{-1}}u_t$$ and the input is $$u_t=(1-\gamma z^{-1})w_t$$ ...
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### binomial confidence including run to run variation for overdispersion

I'm trying to determine the model to correct a confidence interval (binomial proportion for example) but to also include overdispersion affects that arise from a Run-to-Run variation. Example, case ...
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### Representing a Suite of Hypothesis with Stan

After having read the excellent Think Bayes from Allen Downey, I'm now diving deeper into Bayesian Analysis and learning MCMC with Stan. The dice problem in Think Bayes goes like this: Suppose I ...
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### Longitudinal data analysis where meaning and metric of response variable varies over time

Determining what factors predict change over time is a topic of investigation in many fields and there are a variety of readily implemented methods for analysing repeated measures in the same metric. ...
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### Monte-Carlo: R script not returning anything

My R script is mcnorm.R <- function(M,N) { library("mvtnorm", lib.loc="~/R/win-library/3.2") R <- as.matrix(read.csv("Data.csv", header=FALSE)) mu <- colMeans(R) ...
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### F-Test for Equality of Variances with Weighted Survey Data

I would like to use an F-Test for Equality of Variances on a variable for two groups. Normally, this would be done with an sdtest command in Stata or a ...
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### Predictive modelling and cost function

I have to help a company to detect customer in a list of prospects. The company has this benefit/cost function: Value of a new customer = 20 $Acquisition cost = 5$ So if the model: Miss to ...
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### What is the best statistical model for my binary outcome variable?

My hypothesis is: As the experimental count variable increases, the probability that the binary dependent variable equals 1 increases. I expect both the independent and dependent variables to be not ...
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### Johansen cointegration test with structural change in the intercept

I built a VAR in which I discovered that structural change in the intercept so I added a dummy variable as differential intercept. I want to test cointegration by Johansen method and have read that ...
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### Algorithm to find common sequence

Assume that "1,2,3" are the ids of users, active means that person visited the stackoverflow in last one month (0=passive, 1=active), and there are positive and negative votes. ...
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### Variable selection via mutual information

I am building a SVM model and was wondering whether filtering variables based on mutual information between response variable(binary 0/1 variable)is a good approach? Also, would the condinformation ...
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### How to return all a particular column in a data frame

Suppose I have a data frame mysample. When I try to access only the second column using mysample[,2] I get a single element. How do I return the second column of the data frame?
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### Correlation/association for categorical and interval data [duplicate]

I am testing data for correlation. The outcome variable is categorical with 8 categories. There are 20 predictor variables, some are categorical and some are interval. The questions are Is there ...
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### Econometrics - Relationship between cointegration and ECM

I'm pretty new to econometrics and I've been taking a class at University which uses the book "Econometric theory and methods" by Davidson and MacKinnon. It's a pretty good book but there's one thing ...
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### How do you do a log-linear analysis in r?

I can't seem to find anything on log-linear analysis. Does anybody know how to do them in r? I have two variables: one a dependant one (yes or no recoded as 1 or 0) and an independant one with 5 ...
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### Isomap and Local MDS- embedding to linear spaces or not?

In Section 14.9 [1], it is said that Isomap and LocalMDS are embeddings into non-linear manifolds. The embedding is clearly a non linear operation, thus worthy of being NLDR. But As both Isomap and ...
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### How to check if a sample is representative or not biased?

We are studying the difference in behavior between genders on an online community. We are only interested on those users who participate in the site and whose gender could be easily inferred by other ...
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### Pearson's Chi Square test (Goodness of fit)

I have two arrays that I would like to do a Pearson's Chi Square test (goodness of fit). I want to test whether or not there is a significant difference between the expected and observed results. ...
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### Which offers better performance, RJAGS or PyMC? [on hold]

I've looked around for some benchmarks, but have not found any. Do any of you know which runs faster: JAGS or PyMC? I have a model in R, but would like to know if PyMC would run faster, and what ...
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### Which one is correct phase for neural network or support vector machine? Features or Inputs?

Which one is correct phase for Neural Network or Support Vector Machine? Features or Inputs? Based on ...
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### reference for regime shifting models

In looking for a good introduction to regime shifting models. It would be nice to see things like simple example of regime shifting models, ways to detect a regime shift in data, fitting regime ...
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### recurrence quantification analysis

I am relatively new to the use of recurrence quantification analysis (RQA) is a method of nonlinear data analysis which quantifies the number and duration of recurrences of a dynamical system ...
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### JAGS dmstate markov specification

Does any one have experience in running multi state models in jags? I am trying to run a msm on my dataframe with activity being 1/0 time from diag being times observation of the activity and patient ...
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### using both raw and weight of evidence values in logistic regression

I am building a logistic regressin model for probability of take-up for a lending product. I have a number of continuous variables. In the past, I have always used EITHER weight-of-evidence ...
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### Confidence interval odds-ratio matched case control

Consider having a list of pairs of binary data denoting observations from a matched case control study. The list may be used to set up a contingency table and an odds-ratio can be calculated by ...
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### Relative advantages of nnet, neuralnet, caret and RSNNS packages

What are the relative advantages and disadvantages of different packages available for neural networks: nnet, neuralnet, caret and RSNNS? Which is best in terms of simplicity? Which is best for ...
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### Pros of back propagation learning algorithm

I'm doing some research into neural networks and it seems like every single one i've come across implements a back-propagation algorithm. Is this because they're very easy to implement or are there ...