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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Expected value of [variance of sample means] is the average of [sample mean variance]?

This is drawn from Gelman et al in Regression and Other Stories: If I take $k$ independent sample proportions $p_i$ with differing sample sizes $n_i$, Gelman et al says that the observed variance of ...
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Does average or max pooling actually summarise the sentence?

I am working on an multi-label text classification problem at work and adapted model architecture from this notebook of Toxic Comment Classification challenge on Kaggle. I have trained the model, a ...
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Cleaning up several crude odds ratios from several sources

Does anyone know a formula for pooling odds ratios across studies? I'm trying to do a quick pen and paper pooling of different numbers of odds ratios from different studies where I don't have the ...
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why some pooled variance has "average" and some just uses direct sum without avg?

say $X,Y$ are two random variables. I see courses saying $X+Y$ and $X-Y$, each has a variance of $\sigma_x^2 + \sigma_y^2.$ But, on the other hand, I also see courses talking about for $X$ and $Y,$ ...
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A balance summary across treatments in cobalt package

I am trying to calculate standardized mean difference after multiple imputation for multiple treatments. I am using the package "cobalt" but I can not find a balance summary across treatment ...
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Can I use alternative pooling technique after multiple imputation?

Research problem: Comparison of means (T-test, ANOVA) between 90 countries. Analytical problem: I have a large data set of over 120 000 observations. Each observation was measures by 8 variables: 2 ...
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Confused about pooled statistics from multiple linear regression on multiply imputed data in R

I have a dataset with 75 cases. I did multiple imputation of missing data in SPSS. I am running a multiple linear regression on the data. I have 7 binary independent variables, one continuous ...
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Is RoI Pooling appropriate to retrieve fine details from objects of varying sizes?

I’m using a RoI Pooling after a CNN that extract features from images of varying sizes, containing defects I want to classify. The images and defects sizes range from a couple of pixels to ~100 pixels....
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Why is the Mean Square Between (MSB) used in 1-way ANOVA instead of total variance?

I'm having a hard time parsing the logic behind the formulas in the 1-way ANOVA. I'll first establish what I understand so far which will lead into my question. The objective of a 1-way ANOVA is to ...
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Can I pool data sets answering identical question for different examples for moderation multiple regression analysis?

I am currently doing research on the moderation effect of the aim on factors (independent variables) that influence technology acceptance (dependent variables). My research is as follows: Group A had ...
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Residual standard error for multiple imputed regression

How to calculate the standard deviation of the residuals for a pooled regression? (The idea, formula and/or R code are all welcomed) As far as I understand it is the standard deviation of the ...
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How does max pooling reduce the number of parameters to be learnt in a CNN if we already have parameter sharing?

I've been a bit confused about max pooling for a little while but I've finally understood why it provides more generalisation since you're essentially getting rid of less useful information and ...
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With 2-sample bootstrap testing, why pool treatment with control samples?

I have data from a randomized experiment. Members of the treatment group received a treatment, members of the control group did not. I want to test differences in distributions of ordinal outcomes ...
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Different Ways to Calculate the Pooled Means

I have the following question about the properties of individual means vs. pooled means. To illustrate my example, I will use the R programming language. Suppose we have measurements from two ...
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About pooling layer in CNN for landmark detection purpose

I was reading about landmark detection using CNN from this website. In landmark detection, the output is the x-y coordinate of the object that we look for. In CNN, as far as I know, we use the pooling ...
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Rubin's Rule of pooled confidence interval

Rubin's Rule for multiple imputation states that you are to construct a single interval after pooling into a single set of estimates and standard errors: $$ \bar{\theta} \pm t_{df,1-\frac{\alpha}{2}}*...
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Difference between Pooled variance and Combined variance

Could someone explain for me what the difference between Combined variance and pooled variance is? I have couple of groups (more than 2) with different sample size, I want to calculate the overall ...
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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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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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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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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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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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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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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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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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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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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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