# Questions tagged [aggregation]

Refers to "lumping together" potentially inhomogeneous groups of data.

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### Why Does emmeans add_grouping average over the levels of the reference factor?

I've implemented a learning technology to reduce the gender gap(the difference between male and female student grades) in CS education. I conducted a quasi-experiment across six semesters, with ~200 ...
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### Aggregation of daily futures prices to quarterly prices

We are working to incorporate the EIA future prices into our quarterly data set of financial balance sheet data. There are four different contracts, which are available at the EIA website. The idea is ...
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### How to calculate the precision of the mean of univariate time series data, based on the precision of the discrete measurements it consists of?

Assume that the precision of the measurements is fixed and independent – each discrete measurement has the same degree of random error, and is independent of all other measurements. For example, ...
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### How can I use spatial heterogeneity within regions as predictors about those regions?

Please forgive if I am misusing the term "spatial heterogeneity". I am trying to predict county level crop productivity using satellite acquired vegetative health (NDVI). Since this is pixel data, I ...
10 views

### Inference from small sample size with aggregated country data

I have a data set with country aggregate patient data for yearly total number of diseases, treatments provided by health services, and some other covariates for two countries over 10 years. The ...
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### A/B Testing on Aggregate Measures

Suppose we have built a new version of the "Recommended" page of our media website (e.g. Netflix) and are running a test to evaluate its effectiveness. We can collect data in the following schema: <...
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### How to interpret hourly rate data given in one miniute intervals

I have time series data on natural gas flow, which is in units of "tonnes/hour". But the data are given in one minute intervals (each row represents a single minute of time duration). Here is a sample:...
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### Estimating yearly diagnosis rate from multiple studies

I want to estimate yearly diagnosis rates from some 8 studies. Each of the 8 studies contains the following data: $n$ = total number of patients (e.g., 100) $t_{start}$ = start timestamp of the ...
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### Monthly data vs aggregating weekly data to monthly in linear regression

Let's suppose I have weekly data available for making a forecast using a linear regression model. Let's also assume that the weekly forecasts can be aggregated to monthly ones. Would it make sense to ...
21 views

### Correlation of Aggregate Data on a monthly to quarterly basis

I am working with a data set of 42 countries of monthly migration. I want to extract factors using PCA, and find non stationary errors of my model, so I am working in first difference. However there ...
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### How to deal with a potentially multiple categorical variable

I'm building a model that has, as inputs, some categorical variables. I had already dealt with this sort of data before, and applied different techniques as creation of dummy variables and factor ...
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### Best Way to Aggregate further and Analyze a Data Point that is Already an Average

I want to understand how much time (on average) each Customer Service Agent (CSA) is taking to reply to messages that are sent by a Customer on a single chat. E.g., "Charles took on average, 22s to ...
78 views

### Regressions with different periodicity

I am trying to estimate a regression with variables of different periodicity. The dependent variable is given monthly, whereas most other independent variables are also given monthly, but some are ...
107 views

### Machine-learning using an aggregation function

I am looking for a machine-learning algorithm (ANN, random forest,...) that is able to account for an aggregation function during the learning step. I want to estimate variable Y from variables X1,X2,...
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### Multiple data points per subject? Aggregation to mean with or without considering subjects

I am currently arguing with someone on how to correctly treat data with multiple observations per subject. More specifically data was gathered from 100 participants 8 times per day for 5 days (...
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### Is it valid to get the average of the corresponding elements of two time series?

Say I have two time series that have the same length within the same time period. I need to replace the two time series with a single time series that explains the variations in both. So what I ...
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### True Mean of an Observation

I have a list of aggregated data with 100 data points. The information I have is the mean and the number of observations used to calculate the mean. Moreover I have the raw data from which the ...
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### Recommended model to analyze relationship with aggregate rate

In order to analyze the relationship between some independent variables and a binary dependent variable, it is standard to use logistic regression, which allows us to model the probability of the ...
182 views

### Aggregation of “tree results” in random forest regression

I would like to know how the results of different decision trees are aggregated (average) in random forest regression. If I have a numeric target variable and 10 predictors, each decision tree is ...
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### How to aggregate histograms for density estimation

Within a very large sensor network, each node does take measurements derived from a fixed number of samples taken at a high frequency from an instrument. The number of measurements send to an ...
488 views

### Machine Learning model with aggregated data as training

I would like to predict a LABEL: A,B or C using a classification machine learning model. My data to train the model is like: ...
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### Aggregating Cluster Analysis Results [closed]

I want to write something about cluster analysis. I have started to read something about it and I faced with a concept which is called ''Aggregating''. What does it mean for cluster analysis? Do I ...
37 views

### Aggregation of overlapping intervals

Hello anyone and everyone, I have a data set of traffic flow data, particularly intensity data. I have the traffic counts per minute as the base data and then I am aggregating them into 3 and 5 ...
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### Combining distributions

I have a ruler and a set of poles $S$. My ruler is not perfect, so a length measurement of one pole yields in fact a sample of a probability distribution (e.g. natural scientists usually find normal ...
444 views

### How do I aggregate percentiles from previously aggregated percentiles?

I have previously aggregated data for every 5 minutes with a count of sensors at that location and 5% percentiles of a value of interest: 5th, 10th, ..., 90th, 95th. A sensor can have multiple ...
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### Time Series Data: Unequal Sample sizes

I have a dataset which consists of daily observations over a 3 month period for different variables. The data are aggregated so I do not have access to user level data. The problem is that the ...
117 views

### Aggregate repeated measures data or model it?

The structure of my data is causing me some trouble because I'd prefer to aggregate it but I'm not sure of the implications. It's from an experiment comparing dwell time. The subjects were randomly ...
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### Forecasting proportions of aggregations vs direct forecasting

Assume one has to predict the sales of a shop on a daily basis. The sales per day $S(t)$ clearly follow a strong weekly pattern, but also a yearly pattern, a general trend and of course some noise are ...
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### How to summarize items and still calculate percentiles?

My company wants to track request latencies for the project I'm working on. Specifically, the report I'm building should have the 95th and 99th percentile values of the latencies over all events. ...
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### Many samples of the same identity for machine learning

This seems to be a simple question, yet I couldn't find a clear answer on the net. I'm using machine learning to classify ill/healthy patients based on their medical record (probably using a Random ...
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### Feature selection: Should we keep all metrics (like mean. median,..) of a distribution or they make redundant features?

There are many cases in which I don't know which metric I should use to calculate the value of a feature when the value has a distribution for each data point instead of an absolute number. for ...
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### OLS difference between individual level and aggregate level estimates

I am new here, so please accept my apologies if this does not belong here. My question essentially concerns what appears to me a special case of the ecological fallacy. Consider a simple model that ...
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### Fuzzy Aggregation

Each observation in the data consists of a binary outcome variable $Y$, a set of labelled measurements $(M_1,L_1), (M_2,L_2)...$ (the set size can vary between observations) where each label is one of ...
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### Calculating/Averaging/Aggregating Effect Size Across Multiple Measurements

What is the standard practice for calculating a total effect size (using Cohen's d) across multiple measurements in one study? Do you calculate the effect size for each measurement and then take the ...
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### R mlogit and McFadden R^2 (strange?) value

I was a little bit surprised by the high value of the McFadden R^2 given by the "mlogit" R package for this simple model: f = mFormula(mode ~ log(cost) | 1 | 1) ...
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### Summarise data with R - other than n counts [closed]

I've got donor segments Donors aged 34 and younger, vs. donors aged 35 and older Donors with a high frequency of donations vs. donors with a low frequency of donations Every row in my data frame ...
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### Is it dangerous to take the mean of ratio measurements?

I'm going through a Computer Architecture course and in one of the lectures they mention that when measuring the difference in runtime performance between two systems, using for example multiple ...
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### Regularized GLM with aggregated data

I am fitting a poisson GLM to model claim rates. Since I have 1.5m+ records, I have aggregated my data (to improve efficiency). My understanding is that using aggregated data with a poisson GLM will ...
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### Aggregating normalised data

I want to aggregate Google Trends data relating to separate queries that share a thematic category - e.g. "beer" and "wine". I don't care about the relative popularity of the terms - it is more ...
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### Averaging bang for the buck

I'm building a table/graph to compare multiple video cards according to a given benchmark. The benchmark consists of multiple measurements using games. For each benchmark measurement, I build a ...
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### 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 ...
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### Aggregated Means Differ in Regression

I try to run a difference-in-difference model based on single observations which I have to aggregate in order to generate an outcome variable "w.mortf" = mortality. My original data set provides a ...
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### Privacy through moving averages?

I am considering the following hypothetical situation: I have a time series of data. In general, 'the public' should have access to features of this data. However, making the time series available ...
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### Linear regression on aggregate and missing data

I have data from a survey with $m$ quantitative questions (rating 0 to 100). There was $n$ participants. I want to apply linear regression to predict $X_m$ based on $X_1,\dots,X_{m-1}$. There are, ...
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### How to represent multiple data by single value

I have three inputs x1,x2,x3 and to each single input there are three outputs y1, y2, y3. (1) x1 --y1, y2, y3 (2) x2 --y1, y2, y3 (3) x3 --y1, y2, y3 The Whole whole set has to be represented by ...