Questions tagged [pooling]

Pooling, eg for variance, is used when several groups or populations are assumed to have a common property (a common parameter value) and the information from all the groups or populations are used together to estimate that common property.

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13 views

Is there a method or algorithm to get k points in a pool such that it has the most similarity to another dataset [closed]

In Active learning, I want to query points from a pool unlabelled dataset such that these are most similar to points in training data. The similarity could be cosine similarity. The idea could be like ...
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summarize extent of pooling or shrinkage in multilevel models estimated with lmer()

I am using lmer() in the "lme4" package to estimate multilevel models. The models include random intercepts for each group in my data. To fix ideas, here ...
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Is it possible to add two datasets with different number of observations together? [closed]

I have data from a survey done in 2005 and followed up in 2011. In 2005, 500 participants were involved in the survey. In 2011, only 90 participants agreed to participate. There is a huge loss to ...
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Inverse of Global Average Pooling?

I am working with a project where I want to upsample some parameters to create an electrical signal (shape: input=(3) output=(50,19)) The first part of my ...
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10 views

Mean versus global average pooling in GNN

Let's say I have a GNN that outputs node-level embeddings per graph, and I want to turn the node-level embedddings into graph embeddings so that I can then do graph classification. One way I can think ...
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Panel Data: can not include quadratic variables in GLS or LME modelling

I have used the Pooled OLS technique in R to model my panel data (covering 3 years with 191 firms) and the technique has failed key diagnostic tests due to the presence of heteroskedasticity. So now I ...
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74 views

Pooled samples: estimating prevalence of disease

Struggling to understand the concept of pooled sampling and estimation of prevalence. Would really appreciate some help to understand this. Example: 0.5% of the population has a specific disease. ...
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22 views

Graph classification given node-level outputs using global pooling in pytorch

I have node-level outputs for a graph classification task. Based on this article on GCN, it seems like I have to introduce a pooling layer to transform my outputs into graph-level outputs, which makes ...
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fixed or random effects for pooling groups from the same survival analysis

I want to analyze published survival analysis but some of the paper report 3 groups and I'm interested in pooling the two groups with poorer prognosis and compare them to the group with better one. I ...
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37 views

Correct estimation of regression model

I am making model to analyze migration from third countries (together 20) to Slovakia, Hungary, Poland and Czechia. I created panel dataset for each pair of country. For example Ukraine-Slovakia, ...
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Pooled OLS vs RE and FE

I am conducting research for migration from third countries outside EU to Slovakia, Czechia, Hungary and Poland. I have $t=11$ and $N=20$. I am using Gretl. The only good, economic meaningful ...
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36 views

Interpretation of pooling in Graph Neural Networks

The paper Hierarchical Graph Pooling with Structure Learning (2019) introduces a distance measure between: a graph's node-representation matrix $\text{H}$, and an approximation of this constructed ...
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When comparing groups of subjects with within-subjects repeated measures, is it appropriate to use the per-group observations directly?

I'd like to show a summary figure comparing two groups. Within each group, each individual responded to multiple independent trials. As an example: ...
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29 views

Comparison of a meta analysis pooled estimate to an estimate from primary research

I want to compare the pooled estimate (mean change in two time points) of a meta analysis that has been published, to the same estimate from a primary research that i am carrying out (on my own ...
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82 views

Fama MacBeth vs. Pooled OLS

I have an unbalanced panel of monthly bond returns and would like to regress them on several possible return-drivers. There is cross-sectional correlation in the residuals. In this case, Peterson ...
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83 views

Creating a Pooled Data Set From Multiple Imputation Output in SPSS

I have SPSS 26. I have 3 datasets of survey responses, each representing different years' responses. As usual with survey data, there was a lot of missing data that I had to deal with before doing ...
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Bilinear interpolation concept: Error in PyTorch implementation?

I am studying the ROIAlign concept. This is a submodule of an object detection CNN architecture like Faster-RCNN. Basically it is about the following: Given a 'region of interest' of a varying size in ...
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When using a related samples t-test, why not pool the variances a little bit?

In related samples t-tests, my understanding is that when dealing with the standard error, you don't pool the variances, whereas with independent samples t-tests, you do pool the variances. If the ...
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53 views

Should I use a multilevel model if I have lots of observations?

I have a dataset with data for 284,000 trips. The trips are grouped into nine cities. The number of trips per city varies between 3,446 and 89,000. I am predicting trip time with seven independent ...
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35 views

Pooling Different Crossover Data within A Study

I am trying to analyze a double-blind study that has 3 separate crossovers: Dose X mg Dose Y mg Dose Z mg In each cohort, subjects are randomized to either 'Treatment-Placebo' or 'Placebo-Treatment'....
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How to combine/pool the standard error of fitting parameters from multiple fits of the same model?

Let me first explain the context of the problem: I have a time series of the (z-)positions of a particle relative to a surface. For 5 independent subsamples of this time series, I calculate the ...
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Is it possible to perform indirect comparison of before-after/pre-post studies with continuous outcomes (e.g. mean difference)?

I'm currently in progress to perform a simple pooled analysis between surgical approach A and surgical approach B in treating bone fractures. However, as the technique compared involved surgical ...
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How to calculate pooled mean difference?

I'm currently doing a simple pooled analysis study; which, unlike meta-analysis, does not involve weighing between studies. However, my outcome of interest involves continuous outcome (pre-...
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34 views

Cross-sectional pooled regression

I have data from three surveys conducted in three different years (2012, 2014, 2016). Each survey was administered to public managers, but not necessarily the same ones (some retired or changed ...
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How does pooling affect variance?

Suppose you are looking at the prevalence of a certain disease and you can detect this disease in fecal samples. How does having a bunch of pooled fecal samples (i.e., taking a fecal sample from 5 ...
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Can pooled standard deviation be used to determine sample size?

I would like to use Minitab statistical software to determine a minimum sample size for precision (repeatability) testing. From casual observation, we know our allowable error is much wider than the ...
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How to find the weighted average of standard errors from multiple GLM coefficients?

I have to estimate the weighted average of coefficients and the pooled standard errors of the coefficients from multiple independent GLM regressions. Finding the weighted average isn't difficult - ...
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Are there special techniques to combine estimates and standard errors from a complex discrete-event simulation?

My discrete-event simulation works as follows: A sample is drawn from a simulated population The simulation is run a few times for that sample Each run produces k estimates and their corresponding ...
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tf sumpooling layer 1d vs 2d

I am currently working on a paper by Sturm et al. (2016) published in the Journal of Neuroscience trying to replicate their results using python and TensorFlow, Keras libraries. I have strong doubts ...
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32 views

Multinomial logistic regression with pooled data (year dummy?)

I am trying to run a multinomial logistic regression with the dependent variable of three categories (non-user, basic user and advanced user). I have data from 2015 to 2018 with many socio-demographic ...
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60 views

Hypothesis testing - Difference proportions: Pooled vs Unpooled for one-tailed tests

Problem 2 of the Stattrek tutorial (https://stattrek.com/hypothesis-test/difference-in-proportions.aspx?Tutorial=AP) tries to determine whether a drug is more effective for women than for men. They ...
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Creating Models For Pooled vs Panel Data

I have a data set that contains data for 10 of the same stocks for a period of 10 years. This would be considered panel data. I have read that I can not use OLS on panel data because observations are ...
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Does max-pooling increase the receptive field? [duplicate]

I'm new in deep learning. when applying convolution on the image , the receptive field is increased but when applying max pooling on the image, I don't know the receptive field is increasing or keep ...
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In convolutional neural networks, are max-pooling layers used to reduce the number of parameters?

I was asked this question in an exam. I answered "Yes" but the right answer was supposed to be "No". I guess there is no debate that max-pooling layers do reduce the number of parameters in the fully ...
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Gelman multilevel regression analysis, understanding of formula for partial pooling estimates

I'm looking through Gelmans data analysis using regression and multilevel models and want to know whether I understand the definition on page 253 (12.1) which is as follows $$ \hat{\alpha}_j^{...
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pooling variable depth samplewise / are there any importantce to take into account?

My purpose is to apply pooling strategy (max/average) with a variable depth length of the samples in a batch. My question is whether is there something what I should take into account. Does it ...
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Combining F-values from multiple imputation datasets using R [duplicate]

I am currently working on pooling F- and p-values from the ANOVA tables in SPSS regression output. While I tried using various aspects miceadds, it proved to be quite complicated. I recently came ...
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38 views

Linear regressions with similar coefficients

If one has multiple similar dependent variables for which one wants to fit linear regressions y1 = c11*x1 + c10 + e1 y2 = c21*x2 + c20 + e2 y3 = c31*x3 + c30 + e3 ...
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Meta-analysis for case-control studies, confounding factors

Is there a way to adjust the pooled summary effect size (odds ratio) for confounding factors while performing a meta-analysis in R studio? I am performing a meta-analysis and I don't want to pool ...
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60 views

Pool redundancy analysis results from multiple imputations of missing data

I have a dataset that includes missing values, and I would like to carry out redundancy analysis using multiple imputation to fill in the missing values. So far, I have successfully created multiple ...
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84 views

What is the risk of not pooling data

Neglecting sample size, is there something that I can miss if I choose to model separately each of the levels of my categorical variable? To be more specific, I want to predict a binary outcome $Y$ ...
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355 views

Paired vs. Pooled Inference… When is it okay to pair samples?

I understand that paired tests are usually done on sampling distributions that have some sort of linkage. But is there a definitive way to differentiate when to use a paired t test vs. pooled? The ...
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Can I pool these groups?

So I am not completely sure whether I can pool my groups or not to compare them, or if it would be better to compare them pair-wise. The purpose of this comparison is to test the efficacy of my stress ...
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1answer
181 views

Getting pooled F-values and p-values for multiply imputed data in SPSS?

When working with a dataset created via multiple imputation, SPSS pools some values but not others. For example, in multiple regression, I can get coefficients, t-tests for the coefficients, t-values ...
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957 views

Pooled Covariance Matrix with very different amount of samples per class

I have a dataset with 10 classes, and want to estimate the covariance. It turns out that due to numerical stabilitiy, it is much better to use a pooled covariance matrix. Suppose I have $N$ samples ...
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254 views

CNN: correct way of reducing dimensionality of last feature maps

I want to reduce the features of the last convolutional layer of my CNN before connecting it to a dense layer to minimize the risk of overfitting. Lets say the feature maps of the last layer have the ...
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162 views

With lme4, is it possible to weight group-level random effects by similarity?

I'm creating a model with two group-level random effects: district (factor) and age (factor) and a response, ...
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193 views

3 Level Hierarchical Models in STATA; Null model fails to converge

3 Level Hierarchical Models in STATA; Null model failed to converge About the Dataset I am working with DHS (Demographic and Health Survey Data) data. DHS uses a two-stage cluster sampling process. ...
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What is the degree of freedom of a t-statistic when computed by using multiple samples of the two types of experiments?

Let's say I have samples 1, 2, 3, and 4. Out of these, 1 and ...
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124 views

R Panel Data: Difference between Pooling OLS and Fixed Effect with only “individual” effect

I just estimated my paneldata with Pooled OLS or with the Fixed Effect approach. When using FE with the effect="individual" I get a higher adjusted R^2 than using FE with effect="twoways". So I would ...