# All Questions

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### What statistical modeling would allow a more accurate Brexit prediction

Bookies and hedge funds both underestimated the support for Brexit (bookies at one point gave the Brexit 7% odds). Some factors such as variance in voter turn out, and variance in the populations ...
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### parameter estimation MLE vs. other objective function

I am working on an experimental data set, where I have many subjects independently choosing among $N$ options. So the actual choice of each subject can be viewed as a vector with exactly one entry ...
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### summarizing Multivariate time series

I have a data set including 25 variables at each time and all of this group is repeated through time. I want to explore the relationship between these variables through time and for example say that ...
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### How do I perform backpropagation in a Convolutional Neural Network with 2 convolutional layers?

Specifically, I'm using a CNN for image classification and its architecture is: data->conv1->pool1->conv2->pool2->classifier/softmax When propagating errors from conv2 to pool1, how do I do that? I ...
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### Pairwise comparison among variance

I would greatly appreciate any help on this! I'm doing a research where I need to compare variances (or standard deviation) of several samples (9 samples). I did some research and found the "Bartlett ...
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### RStan Bayesian Generalized Method of Moments

Does anyone have the stan code for how to implement two step GMM or even iterated GMM through rstan?
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### Choosing evaluation measure for non-parametric clustering

I have to cluster some data using non-parametric clustering technique which is given in this paper. After all the cluster evaluation measure used in this paper is Normalized Mutual Information as they ...
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### Toy example dataset for testing PCA implementation

I want to check my implementation of dimensionality reduction with PCA, so I'm looking for a test case. I have found other implementations on the web as well, so I will be comparing with those too. ...
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### KL Divergence between an i.i.d sequence and non i.i.d sequence

I have two sequences of probability density functions $Q=\prod_{i=1}^{n} q(x_i)$ (independent and identically distributed, i.i.d )$P=p(x_1,\cdots,x_n)$ (non i.i.d). How can I calculate the KL ...
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### What is exact difference between standard error of estimate and sampling variance?

two concepts are not very clear to me.I have read a lot of literature given by different articles and standard books and notes.
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### Problem involving Scheffe's theorem and asymptotic distribution

If $\{ X_n \}$ are independently and identically distributed $U(0,1)$ random variables and $V_n = n(1 - X_{(n)})$ (where $X_{(n)}$ denotes the $n$th or largest order statistic), then how do I derive ...
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### What statistical test should be used to compare two independent sample over time (pre- and post-test) for categorical variables?

A typical question is: 9. How well do you think your family knows what you are good at?  Very Well  Well  Somewhat well  Not at all well I have a treatment group and a comparison group (...
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### What is lm() compared to VAR()

What's the difference between # Fit Model # fit1 = lm(var$1 ~ var$2, data=data) and ...
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### Defining low frequency and substantial frequency events [on hold]

I have some frequency data and I would like some objective definitions for "substantial" and "rare" or "low frequency" events. For example, if Event A happens less than 5 percent of the time, could I ...
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### Discrepancy between metafor (rma.mv) and metaSEM (meta3) estimates for multilevel meta-analysis

I'm wondering why I get slightly different estimates for a meta-analyzed set of effect sizes, when using the rma.mv function from the metafor package, compared to the meta3 function from the metaSEM ...
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### How to Use LSA Create Topics?

Just want to know the general process of creating document topics via LSA. For creating document clusters, I know first I should get SVD dimensions and then use k-means clustering on these SVD ...
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### Applying bayesian inference to a time based problem

I have a N*M matrix with N customers and M products. Each row of this matrix is a M dimensional vector like [1 3 4 1 5 ....] where each value represents how many times that customer has chosen this ...
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### How to AB test two copulas?

Say that I model two seperate multivariate copula distirbutions in an experimental design. What is a statistical test that I can use to determine whether they are different?
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### Applying a parametric model to categorical data

I am working with kaggle Animal Shelter data set and need to use a parametric method to this data. If I understood correctly, parametric models need numerics data set, but in my assignment I am ...
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### LSA Clusters Have the Same Words

I use LSA to create 5 document clusters and identify top 10 words nearest to cluster centroid. I found 4 words appear in all clusters(good, stay, staff, clean) . How to deal with this outcome? Should ...
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### How to run a nested LabelKFold with scikit-learn? [on hold]

I have a dataset with ~300 points and 32 distinct labels and I want to evaluate a LinearSVR model by plotting its learning curve using grid search and LabelKFold validation. The code I have looks ...
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### Shifting mean of composite functions

For a project I am involved in relating to communication, I have the following model: $L = f(r).X$ where $X$ is a lognormal random variable with zero mean in the logarithmic scale and standard ...
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### Why does epsilon greedy policy improvement works?

A simple, well explained proof will do the work. Thanks.
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### Which assumptions do I need to check for a GLMM with a binary response (and how?)

I am modeling binomial responses using Generalized Linear Mixed Models with a nested random effect (not of interest, simply a control: year nested within location) and both categorical, count, and ...
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### Randomized Intervention and endogeneity across outcomes

Community, I am looking for a proper identification strategy for a specific question which I want to answer with my data and was wondering whether anybody here would have an advise on that. My ...
41 views

### Should I use drop connect and L2 regularization?

I've just learned about the drop connect technique for neural networks. It is my understanding that it is intended to reduce over fitting and is referred to as regularization. Is there additional ...
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### Robust one sample tests of variance or scale

A common one sample test for variance is the chi-square test, e.g., http://www.itl.nist.gov/div898/handbook/eda/section3/eda358.htm. What are some robust testing alternatives for variance when the ...
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### Classification eda

I am constructing a 2-class classifier and using cross validation to tune certain parameters in my model. The predictor variables are both continuous and one is ordinal. Based on looking at the ...
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### Linear regression polynom slope constraint in R

My problem is how to find best decreasing 3rd degree polynomial regression in R. I have data, lets say ...
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### Interpreting the direction of an interaction effect in Binary Logistic Regression

I have reviewed prior posts in the forum and can't seem to find an answer to a problem I am having with interpreting an interaction: The goal: interpret the direction of the interaction term. ...
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### Question regarding variables transformation for GLMM's

I have a response variable (binary:1/0) and a set of explanatory variables, with different units: some have values in %, others in meters (distances, altitude and differences between elevation pixels),...
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### Dealing with survival analysis data - reliability

I am totally new on Survival Analysis and my data is tricking me. I have, in excel, a list of failure's records informing date and hour of ocurrence, what failed/broke on that equipment and the cause ...
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### Mode computation for different variables in SAS [migrated]

I need to compute the mode for different variables for the same id using SAS. The original dataset is ...
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### how to report estimate standard errors of levels from a one-way ANOVA

I'm trying to report means of levels given a model. ...
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### AR(2) process: are leptokurtic residuals OK?

I have a time series of logarithmic returns. After inspection of the ACF and PACF plots, I tried to fit AR(2), MA(2) and ARMA(1,1) models and eventually found out that the AR(2) version can possibly ...
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### Follow up tests for ANOVA and Kruskal-Wallis in MATLAB

For my non-parametric data I am using a Kruskal-Wallis test and for parametric an ANOVA test. In the MATLAB documentation it just says to use 'multcompare(stats)' function as a follow up which gives ...
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### How to calculated test F with only output glm?

I have to calculate the value of the test F (no software needed ) . I read several notes, but I can not understand how I do . The idea is to take Null deviance and Residual Deviance and split in some ...
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### Problem on convergence of sequence of random variables

Given any sequence of random variables $\{ X_n \}$; how do I show that there exists a sequence of real numbers $\{ \alpha_n \}$, such that $\{ \alpha_n X_n \}$ converges in probability to 0 ?
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### Can AdaBoost be used with multiple measurements?

Can Adaboost be used with multiple measurments? If yes, how / why is it working? Example: let's say I want to predict if it's going to rain=1, or not=-1 and I want to model my prediction based on, ...