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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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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36 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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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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59 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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49 views

Max-Pooling: Use Valid or Same Padding?

So Same padding allow you to design deeper networks, since there is a slower reduction in volume size. Also it improves the performance a lot of the times since it keeps more information than when ...
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28 views

Pooling descriptive statistics of categorical variables after multiple imputation

I am doing multiple imputation using the MICE package on R. My dataset consists of both categorical and continuous variables. After doing say 20 imputations, how should I go about pooling together the ...
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42 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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14 views

How can random forest variable importance of a pooled sample be greater than variable importance of individual samples?

Here's what I have: a data set with 30 different questions measuring customer experience (on a scale from 1-10), and a question measuring "Overall Customer Satisfaction" (Q1). The data set is ...
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Comparing cage average values… weighted, pooled, nested?

I want to compare food consumption between three treatment groups. Each treatment group had 20 individuals, however, due to logistical constraints they were group housed in cages with 2-3 individuals ...
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45 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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How should we recalibrate weighting of the pooled dataset?

I have results from 2 surveys at the same year, The sampling method used in these surveys are different and I have sampling weights calculated (with respect to the population) in each study. The ...
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227 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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43 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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94 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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Understanding the relationship between multiple variables

Having troubles interpreting the results of my pool() function I know what everything means except for the estimate, d and riv columns: ...
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76 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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Standardisation (normalising) for feature scaling in non-logged data for within transformation model

I wonder if someone could provide an insight for my case. I am interested in normalising my data to obtain unitless state that will allow me to use them in a quadratic model (not translog). Based on ...
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32 views

Weighting and Clustering in Pooled Data Analysis

I am working with DHS (Demographic and Health Survey) data. I have pooled data from about 25 countries taking 2 most recent waves from each country. My dependent variable is neghaz (negative of height ...
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90 views

Proof that the pooled sample variance is biased when paired comparison is not used when it should be

Given the model for what is meant to be a paired comparison design: $y_{ij} = \mu_i + \beta_j + \epsilon_{ij}$ $i = 1,2; j= 1, 2, ..., 10$ Eg. An experiment comparing the different in mean hardness ...
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18 views

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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97 views

How to calculate pooled deviance explained from gam model fitted with multiple imputation data set?

I fitted gam model using mgcv package with multiple imputation data set. I need to calculate the combined overall deviance explained. Is the approach used in combining r-square from multiple ...
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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 ...
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410 views

Is there an R function that performs LASSO regression on multiple imputed datasets and pools results together?

I have a dataset with 283 observation of 60 variables. My outcome variable is dichotomous (Diagnosis) and can be either of two diseases. I am comparing two types of diseases that often show much ...
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Combining point prevalence estimates and their confidence intervals

I have some health survey data from multiple years. This includes the estimated prevalence of a flu vaccination in a population, then number of people surveyed, and the high/low confidence intervals. ...
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Dynamic Pooled OLS: does it make sense?

I have data on 25 countries for about 35 years. I want to estimate a POLS as I am not looking for a causal interpretation but just sttistical correlation between two phenomena. That's why I will not ...
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631 views

1D CNN for time series regression without pooling layers?

I am working on a prognostics task, where I predict the Remaining Useful Life of some equipment (i.e.: time steps remaining until failure). In order to do that, I use multivariate time series sensor ...
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59 views

Difference between pooled variance equations

I'm currently doing A-level Further Maths A2. I've seen two different equations to calculate the estimate of pooled variance. I do not know when to use which and what makes each significantly ...
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41 views

Simple mean or weighted mean of Fisher z-transformed correlation coefficients

I need to perform the average of a set of correlation coefficients $\rho_i$ with $i=1,\ldots,m$. I follow the standard prescription: apply the Fisher z-transformation to my $\rho_i$ ($z_i$ are the z-...
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30 views

Panel Data: correlation between individual effects and variables

Is it possible to see if there is a correlation between any variable and the individual effects just by looking at the coefficients and standard-errors of an OLS, RE and FE functions?
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Why do we neglect the additive interaction in bi-linear pooling?

In bilinear pooling we use the multiplicative interaction between elements of the vector but what about the additive interaction(the usual feed-forward layer)? I mean in bilinear pooling, we don't ...
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bias estimating the proportion in pooled population

Assuming we want to estimate the proportion of success and there are two stages. We will move to stage 2 only when the number of success is greater than equal to a threshold (say 5) in stage 1. And we ...
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28 views

pooled GEV return level estimation

Let’s suppose I have 4 AMAX time series of 40 years each one, they could be eg wind speeds from 4 meteorological stations in a given region. The time series have been normalised. I want to fit a GEV ...
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70 views

Pooled regression vs. average over individual time series models

I have a standard prediction problem in social science where the data set is a pooled data set (i.e., time series of cross sections where each sample can differ and is de-trended, $y_{t+1} = \beta X_t ...
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355 views

What are the advantages of a random effects model versus a pooled OLS regression with cluster–robust standard errors?

Both models allow for explanatory variables that are time-invariant. I had thought that the advantage of a random effects model might be related to the fact that random effects models mitigate ...
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45 views

what is the standard error for hypothesis testing of two proportions using a z-test?

Let's say we are evaluating two algorithms. Algorithm 1 gets p1 = 80% conversion Algorithm 2 gets p2 = 85% conversion The two sample sizes are ...
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127 views

Pooling homogenous studies vs. using meta-analysis/bayesian

I am working with a student who has collected about 300 participants for his thesis. After collecting 100 participants, he analyzed the data. I had just recently read of a "mini-meta-analysis" ...
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26 views

Pooling Results from Bootstrapped Samples (Adjusted R-square and variable significance)

My manager is interested in using Adjusted r-squared to evaluate models and want to know how much does each predictor contribute to the adjusted r-squared to the final model. However, due to an ...
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How to combine observational studies

I am trying to show the releationship between a drug and an outcome in a particular setting. Using a systematic review, I have found 18 studies addressing this topic. Among those, the highest quality ...
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406 views

Connection between time dummies and time fixed effects

If i use time dummies in a OLS pooled regression, does it imply time fixed effects? Maybe to clear things up: 1)There is a pooled time -series-cross-section regression, the equation uses time ...
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809 views

Proof to obtain pooled variance equation [closed]

I was checking the definition of pooled variance, and although I think it makes sense intuitively, I was wondering how can one obtain that estimator. For the case of only one group, I understand the ...
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Short Sentence Generation using CNNs

I am investigating whether building a classifier for sentence classification using CNN can be used for sentence generation. Say, we are classifying news articles' titles (classes such as sports, ...
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106 views

Asymptotic Variance for Pooled OLS

I am trying to prove, under the assumption $E[u_t^2x_t^Tx_t]=\underbrace{E[u_t^2]}_{\sigma^2}E[x_t^Tx_t]$, that the $$AVar[\beta_{POLS}]=\sigma^2 E[x_t^Tx_t]^{-1}$$ My result: $$\begin{eqnarray}AVar[...
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Pooled variance for post hoc tests for contingency table $\chi^{2}$ tests

The 2-by-2 contingency table test provides an alternate hypothesis testing approach to the $z$ test for proportion difference. Conveniently enough, a 2-by-k contingency table test provides an omnibus ...
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3k views

Why global average pooling is able to work correctly?

In Network in Newtork, section 3.2, talks about global average pooling (GAP). In my understanding, GAP averages every value of (x,y) coordinate in 1 feature map into 1 value, then send this value to ...
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216 views

Meta-Analyzing Dependent Effect Sizes (Log Response Ratios)--Is Averaging Effects An Acceptable Solution?

Given k studies, for each computing a log response ratio $L$ and variance $v$ following the Hegdes et al., 1999 equations: $$L = ln(R) = ln(\bar{X}_{E})- ln(\bar{X}_{C})$$ $$v = \frac{(SD_{E})^2}{n_{...
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127 views

Formula for pooling means, variances

We are performing an inter-comparison experiment for three devices that can measure concentration (cells/mL). We take one solution and run it through each device, and we compute mean concentration and ...
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67 views

When is it appropriate to pool trials within subjects for statistical comparisons?

Usually I have small number of subjects (e.g., 4-6 rodents) and I record electrophysiological activity during presentation of a stimulus or performance of a task. A general question that arises when ...