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.
261
questions
0
votes
1
answer
17
views
Error message when trying to pool multiple imputations (R)
I am very new to stats and R and multiple imputations so I am trying to get my head around all of this.
I have completed a MI with mice in R and have followed the steps for pooling the results that I ...
- 1
1
vote
0
answers
11
views
Attributing variance to fixed and random effects / partial pooling in glmmTMB
I have a dataset with counts of birds in two locations over time, and am interested in describing the difference in trends in bird counts between these locations. The counts are conducted by multiple ...
- 11
0
votes
0
answers
13
views
Pooling annual staff survey data for analysis
Every year since 2016 all of the nurses (n~100/year) are asked to complete a survey on job satisfaction and wellbeing. I'm interested in conducting a correlation analysis (Spearman's) to determine ...
0
votes
0
answers
29
views
Is it acceptable to use pooling layers in variational autoencoders?
When training a model for image classification it is common to use pooling layers to reduce the dimensionality, as we only care about the final node values corresponding to the categorical ...
- 13
1
vote
1
answer
84
views
Multiple imputation MICE categorical variable: problem with pooling after running ANOVA
I am trying to answer a question about satisfaction and its relation with a certain variable (numeric, 1-10). However, my data contains a lot of missing values in the satisfaction outcome, therefore I ...
- 11
0
votes
2
answers
282
views
Cox Regression on multiple imputed datasets (R)
I fit a cox regression using the coxph function of the survival package. Now I wanted to do the same on a multiple imputed data set (which I already have, generated in another software). I found some ...
- 19
2
votes
0
answers
18
views
Approaches to (non-linear) meta-regression to estimate the conditional population distribution of $y$ based on aggregate data
I want to estimate the distribution of a variable in certain subgroups of the population based on pooling of aggregate data reported in various observational studies. For simplicity, assume there is a ...
- 121
4
votes
2
answers
200
views
How can I average the variance extracted from different group of samples?
I have groups of samples, where each group has a different number of samples and a different mean. I also know the variance of each group of samples. I would like to compute a sort of "average&...
0
votes
0
answers
88
views
Is there a way to fit a machine learning model to MICE imputed datasets and pool the results?
I have a medical dataset that has a lot of missing values. I imputed five datasets using MICE in R. I want to fit a classification machine learning model to the dataset. I want to identify the most ...
0
votes
0
answers
162
views
Multiple logistic regression odds ratio on multiply imputed data in R
I am running a hierarchical logistic regression analysis using multiply imputed data in R (using the mice and miceafter packages). I am unable to get the odds ratio and 95% CI per variable adjusted ...
- 1
0
votes
0
answers
23
views
heterogeneous feature coverage in a panel
I am looking for references for the problem where the X matrix has K features as columns and rows are for different entities, but each feature may have different coverage for different entities. For ...
- 1
0
votes
0
answers
60
views
How to calculate the pooled SEM
My questions is how to calculate the pooled SEM?
For 4 different ambient temperatures I have a mean body temperature. I want to calculate manually one value for the pooled SEM for the body temperature....
- 1
1
vote
0
answers
50
views
Pooled standard deviation of two correlated variables [closed]
I'm trying to calculate an effect size index where I need to pool 2 standard deviations calculated from correlated variables (pre-post treatment scores). Using the standard formula:
$$
\sigma^2_{...
0
votes
0
answers
20
views
Using pooled variances to calculate t-intervals: Degrees of freedom
Can I use the pooled variance to calculate confidence intervals around means? I'm posting the formulas I'm using in case I got anything wrong.
We do have three or more rounds of analysis of the same ...
- 1
2
votes
0
answers
220
views
What is the difference between "repeated cross-section" and "pooled cross-section"?
What is the difference between "repeated cross-section" and "pooled cross-section"?
Pooled cross-section is defined e.g. here as "randomly sampled cross sections of ...
- 1,928
0
votes
0
answers
40
views
Multiple Imputation Pooled Dataset Frequencies Not Adding up to 100%
I used multiple imputation on my dataset. Following that, I pooled that data for easier analysis. When looking at frequencies, I noticed that my variables were populating multiple times under both the ...
0
votes
0
answers
12
views
Estimating input demand elasticities with time series data pooling
I want to find input demand elasticities of Labor, seed, agro-chemicals and fertilizer of 5 vegetables. Time series data are available from 1991-2019 for each crop for two growing seasons.
When I'm ...
- 11
1
vote
0
answers
226
views
Is downsampling necessary in CNN?
I am still trying to understand the effect of any downsampling (reducing the input height and weight by 2 for example) by pooling or strided convolution? Does downsampling improve accuracy?
Because in ...
- 31
1
vote
0
answers
67
views
Pooling SHAP values from multiple imputed data
I have multiple imputed data and will be conducting an identical lightGBM model with the same input features in each of the imputed datasets. My aim is to calculate SHAP values (SHapley Additive ...
- 11
0
votes
0
answers
23
views
Which sample size to use when calculating standardised mean differences?
I'm working on a meta-analysis investigating the effect of an intervention on a mental health symptom compared to a control.
For the meta-analysis, I have to calculate standardised mean differences (...
- 1
0
votes
0
answers
33
views
Is it possible to pool results from PERMANOVA tests on multiply imputed datasets?
I wondered whether it is possible to pool results from multiple PERMANOVA tests performed on imputed data.
In case of ANOVA, methods of how to pool results have been proposed and discussed, e.g. van ...
- 143
0
votes
0
answers
43
views
How to choose the best converging imputations for my CFA model and pool them
I have 70 imputations of my original data set. I want to choose 50 of them which converged after less than 120 iterations on my CFA model:
...
- 1
1
vote
0
answers
111
views
Why not using Convolutional pooling instead of MaxPooling to avoid invariance
I was reading the paper of [Geoffrey Hinton: Capsule network], and I watch it's talk on Youtube about the problem of Conv Network is actually the (max) pooling layer, since we don't want to be ...
0
votes
0
answers
23
views
bias is large relative to the variance when we pool information over small samples or when data is highly stratified?
I am reading Yudi Pawitan's In All Likelihood Chapter 5. The book makes the following assertion on MLE bias.
"...bias is large relative to the variance when we pool information over small samples ...
- 1,335
0
votes
0
answers
42
views
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 ...
- 1
1
vote
0
answers
32
views
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 ...
0
votes
0
answers
30
views
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 ...
- 101
1
vote
1
answer
38
views
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,$ ...
- 111
1
vote
1
answer
33
views
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 ...
- 11
1
vote
1
answer
356
views
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 ...
- 641
0
votes
1
answer
23
views
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 ...
1
vote
0
answers
242
views
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 ...
- 111
2
votes
0
answers
135
views
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 ...
- 21
3
votes
1
answer
2k
views
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 ...
- 7,126
2
votes
0
answers
27
views
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 ...
- 171
1
vote
1
answer
838
views
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}}*...
- 147
1
vote
1
answer
1k
views
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 ...
- 23
2
votes
0
answers
843
views
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 ...
- 341
1
vote
1
answer
346
views
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 ...
- 21
0
votes
1
answer
55
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 ...
- 223
2
votes
0
answers
19
views
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 ...
- 91
0
votes
0
answers
17
views
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 ...
1
vote
1
answer
36
views
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 ...
1
vote
1
answer
77
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 ...
- 513
1
vote
0
answers
62
views
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-...
- 793
1
vote
0
answers
24
views
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 ...
- 9
0
votes
1
answer
95
views
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 (...
- 111
0
votes
0
answers
35
views
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 ...
1
vote
0
answers
16
views
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? (...
- 79
2
votes
0
answers
171
views
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 ...
