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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16 views

Modelling Unbalanced Panel Data and Time-Invariant Explanatory variables

I am trying to create a regression model analogous to the following conditions: My dependent variable, $Y$, is unbalanced panel data (Investment flows over varying years for almost all countries) My ...
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Should I pool samples or leave them separate before running a PERMANOVA?

I have a dataset of fish species from different sites within a harbour collected over 17 years. The dataset consists of 1,042 sampling transects collected at 6 specific locations where fish were ...
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Plot pooled mixed lme model fit using cubic regression splines

I'd like to plot the following model: ...
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55 views

Advantage of within transformation over pooled OLS with dummies?

First, apply the within transformation (fixed effects transformation) on a panel data set. Then, apply pooled OLS with dummies for each cross-sectional unit on the same panel data set. When you ...
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Local translational invariance for content when pooling or downsampling

Suppose I do 2x2 pooling with stride 2x2, and I can do as much zero-padding as I want. Ordinary pooling is local and not fully translation invariant, because it is dependent on image boundaries. If I ...
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How effective is using the Fractional Max Pooling vs Normal Max Pooling

I was reading this paper, named "Fractional Max-Pooling", by Benjamin Graham. I was looking into creating better models for CIFAR-10 dataset, and basically found this paper here. Now, I was ...
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Learning Deep Features for Discriminative Localization paper

I am reading the paper Learning Deep Features for Discriminative Localization and on page 2, in the last paragraph, the authors define global average pooling (GAP) for feature map k: For a given ...
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43 views

1x1 convolution instead of Global Average Pooling

is it possible and useful to use a 1x1 convolution before the flatten and dense layer instead of the GAP? The 1x1 conv should theoretically select the most important Feature maps
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37 views

Multiple imputation in R with mice package

I have conducted a multiple imputation in R with 5 imputations and 50 iterations using the function mice() from the corresponding mice package. Now that I have ...
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30 views

Calculating pooled p-values from cross validation folds

I want to calculate the pooled p-value of a regression coefficient across K fold cross validation. I have a model $$Y \sim \mathrm{Intercept} + \mathrm{Cov}_1 + \mathrm{Cov}_2 + \mathrm{Cov_3} + X$$ ...
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127 views

Cross-correlation synthesis for 2 Fisher matrices

I am trying to do a synthesis between 2 Fisher matrices, i.e without only considering a simple sum : I am looking for a final Fisher matrix that performs the XC (cross-correlations). One done that, I ...
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94 views

Gelman & Hill's 'no', 'complete' and 'partial' pooling in the context of longitudinal data

In Gelman and Hill's Data Analysis Using Regression and Multilevel/Hierarchical Models, they present a very compelling idea of 'random' effects offering a kind of compromise between no-pooling (i.e. ...
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76 views

How to pool regression coefficients

I have a question in the area of meta research. I have a dataset that consists of regression data of several economics papers. More explicitly, I have the values of the regression coefficients, the ...
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54 views

Large dataset of many short time series: what model to use for forecasting a new time series not in the data?

Problem statement Consider this hypothetical but hopefully practical example: You have a dataset consisting of home electricity usage for 1,000 homes in a city. For each home, you have a time series ...
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20 views

Is the pooled variance equal to the variance of the centered populations?

Suppose two data arrays of length $n$ with variance $\sigma^2$ and mean $\mu$. Is the pooled variance $\sigma_P^2 = \frac{(n_1-1)\sigma_1^2 + (n_2-1)\sigma_2^2}{(n_1-1) + (n_2-1)}$ equal to the ...
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122 views

Distribution of the pooled variance in paired samples

Suppose a bivariate normal populations with means $\mu_1$ and $\mu_2$ and equal variance $\sigma^2$ but having a correlation of $\rho$. Taking a paired sample, it is possible to compute the pooled ...
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32 views

Regression of the replicated measures (on pooled individuals) of an outcome variable on an individually measured predictor variable

I keep running into the same kind of statistical/experimental problem and I still do not know how to deal with it properly. In abstract terms my issue is to perform a regression of the replicated (not ...
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21 views

What is the difference between a late and exit poll?

When glancing at the Polish presidential elections last Sunday, I saw that the results after the closure of the voting offices (21:00) were tagged as being "late poll" results, with an ...
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47 views

How to calculate mean and SD between $T_1$ and $T_2$ based on mean and SD from $T_0$ to $T_1$ and $T_0$ to $T_2$?

I am performing a meta-review about the transition of control in semi-automated cars, for which I am trying to retrieve specific means and standard deviations. I am not sure if I am using the right ...
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60 views

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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62 views

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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15 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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76 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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41 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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41 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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86 views

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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55 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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33 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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175 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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599 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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119 views

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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70 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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41 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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42 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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33 views

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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54 views

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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136 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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40 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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20 views

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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80 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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91 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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