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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Converting unstandardised regression coefficients to Cohen's d for meta-analysis

I am conducting a meta-analysis of Cohen's d and some raw effect sizes are unstandardised regression coefficients. Of these unstandardised regression coefficients: Some are based on a binary ...
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Precision of a pooled variance

Say you want to calculate the pooled within-sample variance and you can have 20 observations in total. We can assume the variances are equal in each sample. When designing the experiment, what will ...
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Test for Subgroup Difference Compared to Test for Moderator

I have performed a proportional meta-analysis to evaluate the rate of procedural success for two medical procedures. The two procedures comprise the two subgroups in my meta-analysis (FNA and FNB). I ...
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40 views

Confidence Interval of an Average

Consider I have 20 samples from each of 10 batches resulting in 200 samples total. If I take a parameter I'm trying to estimate and calculate the confidence interval using all 200 samples pooled ...
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Pooling in a Meta Analysis

I am looking to pool data for adverse events for a meta analysis and I wanted to see if my plan made sense I want to pool my AE together based on the Clavien Dindo categorizations, as this will make ...
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Do Convolutional Layers Pool data?

Sorry for the trivial question but considering this example in the image attached doesn't the conv layer pool data by summing them? What I am asking is if this images describes a subset where a conv ...
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Asked to create data set where magnitude of paired t-test statistic is very large, but pooled t-test statistic is small. Can't find any resources [closed]

It seems almost impossible to make these tests diverge by much. I have tried making the variance for one distribution much larger, or much smaller. I have found a data set where the paired is a good ...
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29 views

Pooling Two Samples to a Single Sample

Let us say we draw 10 sample values from a given (continuous) population. However, the values tend to be very different than expected, so that we suspect that there might have been an error with the ...
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Can I pool together data from two seperate RCTs of the same intervention when I have access to both datasets? If so, what analysis is appropriate?

Background I have available the data from: A parallel arm RCT of Intervention A compared to a control group that was conducted several years ago. The primary outcome is a difference in the post-...
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Pooling estimates from different models into a pseudo-hierarchical model

I don't know if the question title makes sense, so I'll try to explain what I mean below. I have roughly 100 ERGM models (social networks) that, for the sake of argument, are parametrised in the same ...
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Staggered Average and Standard Deviation of incomplete dataset

I have an AxBxC matrix of measurements, from which an arbitrarily-sized-and-distributed number of measurements have been deemed invalid and removed (i.e. that matrix contains a mostly random ...
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Is it reasonable to calculate a T-test or Cohen's d with one group's sample size, mean and standard deviation being averaged or pooled?

This is my data: year 1: n, mean, sd year 2: n, mean, sd year 3: n, mean, sd year 4: n, mean, sd year 5: no data year 6: n, mean, sd (special event happened) Sample sizes, means and standard ...
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Pooled (or combined?) variance - is it suitable to use in the below scenario?

I have a dataset with measurements and their deviations from nominal value. These measurements have been made on 3 different categories of a component. The components differ in physical properties (...
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How do I decide if it's ok to pool data?

I have biodiversity data (fish species, and their individual length, through electrofishing) from 8 different stretches of the same river, for 7 different seasons. We would like to see if it's ok to ...
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40 views

Can you calculate pooled standard deviation from just the sample standard deviation?

For a meta analysis, we are calculating cohen's d from data reported on published articles. For a specific article, only standard error (SE) and mean difference (between treatment and condition) are ...
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Looking for somewhat pooling between average and maximum pooling

In the textbook Dive into Deep, there is a question: Is there another operation between average and maximum pooling that you could consider (hint: recall the softmax)? Why might it not be so popular? (...
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How to calculate aggregate standard deviation for composite scores in a meta-analysis

I wonder if someone would be kind and able to provide guidance/suggestions on a stats issue that myself and colleagues are trying to handle while performing a systematic review and meta-analysis. In ...
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Pooling variance of two samples with sample means and sample variance [duplicate]

I am new to this so I don't have enough reputation to comment on the original post here. I have a similar problem with equal weighting, and have n = m = 3. I believe this means I need to use sample ...
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Pooling of data

I am doing some secondary analyses. I am looking to combine similar surveys from different countries in a region (sub-Saharan Africa) to be able to detect more subtle differences between my ...
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Pooling and Chow-test

I have a dataset containing weekly observations of three variables; sales, price and assortment, for 10 different brands in 12 different grocery chains. The observations go over 209 weeks for all ...
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Network meta-analysis with trials of different follow-up time [closed]

0 I am trying to do a network meta-analysis, and calculating anticipated absolute differences, I have seen other papers generating anticipated absolute differences for treatment for x number of years. ...
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Pooled Variance from two Variables' SD, but no correlation?

Is there any way to calculate a pooled variance in a within subjects design when I have the SDs and sample size, but no correlation between X and Y? I'm trying to calculate an effect size using single ...
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Average vs Max Pooling in Modified DenseNet Transformation Blocks

A similar question has already been asked and answered in regards to why DenseNet uses average pooling instead of max pooling in DenseNet, and the answer seems satisfactory to me. However I'm using a ...
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Question about Bayesian Melding?

I am going through Bayesian Melding paper by Poole and Raftery (2000). One of the ideas of the paper is demonstrated by Example 3.5, where there are three uniform distributions considered for $X\sim ...
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Intrabatch variabilty estimated from pooled SD and confidence intervals

I would like to calculate intrabatch variability of parameter A, which is normally distributed. I have data of 50 batches (the same process), for each batch I have one representative sample with ...
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Pooling dynamic panel models (dpm) with mice::pool in r

I have multiply imputed panel datasets that I have constructed with amelia. I put them in a list and constructed a corresponding list of ...
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Correct pooling of shared frailty models fitted on multiply imputed datasets

I'm wondering whether the pool() function from R's mice package correctly pools shared frailty models fitted on multiply imputed ...
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Performing An NMDS on multiply imputed datasets

I'm hoping to possibly find bio-indicators, so I want to perform an NMDS on my data, that consists of species data and environment data. Unfortunately, there are some missing data in the environment ...
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What image filter is used in max pooling in image processing

I am curious to know which filter is used in to do max pooling? I am aware that it is a Deconvolution layer. As it takes the maximum value across all pixels - would it use an nonlinear area filter? As ...
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Confidence interval for combined populations

I'd like to compare two approaches for calculating the confidence interval ($CI$) when estimating the mean for a sample of weighted values: The first approach is based upon the standard error of the ...
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Demand Forecasting with Price Promotions

I'm trying to use Excel Solver and Linear Regression to forecast demand of a product with variables like different types of promotions and baseline level. I am looking at pooled regression but I don't ...
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Why is the cohen's d effect-size from this study so different from the value I've computed manually?

In this study [1], they estimate an overall cohen's d effect-size of .70; however, when I try to compute the cohen's d using their means/stds, I get a much smaller effect-size of .47. Am I doing ...
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Simple question on A/B testing

Hi there I have a question that I am confused as how to answer. So I have a balanced dataset of 500 observations split between 2 groups. 250 are a control group and 250 are an experimental group. The ...
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What is the maximum entropy distribution given *conditional* means and MADs?

I know the maximum entropy distribution given the mean and MAD (Mean Absolute Difference) around the mean (it's the Laplace distribution, a proof here for example). I also know the maximum entropy ...
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Estimate both time-variant and time-invariant parameters consistently

We aim at estimating the following model $$ y_{i t}=x_{i t}^{\prime} \beta+z_{i}^{\prime} \gamma+c_{i}+u_{i t} $$ where $x_{i t}$ is a vector of time-varying regressors, $z_{i}$ is a vector of time-...
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Is the mundlak estimator equal to the within estimator?

Mundlak has proposed to estimate the following correlated random effects model: $$ y_{i t}=\boldsymbol{x}_{i t}^{\prime} \boldsymbol{\beta}+\overline{\boldsymbol{x}}_{i}^{\prime} \gamma+\omega_{i}+u_{...
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Calculating pooled estimates after manipulating datasets

After I imputed two datasets, the two datasets are synthesized via statistical matching. With the synthesized data, I tried to pool estimates but got errors as below. ...
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What is the intuition behind Dynamic Image Networks or Rank Pooling?

I am not quite understand why the parameter of ranking machine can be used as a representation, is there an intuitive way to explain it? Rank Pooling for Action Recognition: Ranking machines trained ...
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How did mdewey come up with this equation for the SE of an average of z-transformed correlations?

I have the exact same question as the OP of this thread: I have $k$ correlations which might be based on a different N of cases. After applying Fisher's z-transformation and getting $z_{av}=\sum_{i=1}^...
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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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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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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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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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163 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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157 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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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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