Questions tagged [count-data]

Count data are non-negative integers representing whole amounts.

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Incident Rate Ratios opposite sign from change in volume

I am calculating IRRs on events $x$ over a time period, say t=1-10, in two different years. Using a poisson IRR, I find an estimate of >1.00 (but not statistically significant), even though $x_{...
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JAGS error in the estimation of a simple INAR model

I am having a hard time try to figure out how to translate a simple INAR(1) model in JAGS. \begin{equation} Y_t = \alpha \circ Y_{t-1} + e_t \end{equation} where $\circ$ is the binomial thinning ...
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Analysing repeated measures percentage data from visual analogue scale

I've been searching for the best way to analyse percentage data from visual analogue scales. Basically, each person completed a visual analogue scale during 5 conditions. The scale was a 250 mm line (...
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Comparing output of Pearson's chi-squared to output of R function qchisq

I have a dataset which contains count data. I am pretty sure the dataset is well suited to a negative binomial distribution, since the variance is greater than the mean, but I wanted to check this. I ...
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13 views

Statistical Test for Independence Increments

https://www.youtube.com/watch?v=aCSocDPw8cM @7:45 - They mention in this video that for a Counting Process to be considered as a Poisson Process, it must at least have "Independent Increments&...
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Evaluation metrics for out-of-fold predictions obtained through negative binomial regression

I'm formulating count data out-of-fold predictions using a negative binomial regression and i am a bit confused as to which evaluation metrics apply best. My dependent variable has a long tail ...
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using per capita or raw counts for epidemiological regression analysis

I have two datasets. To simplify, they look something like this: ...
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14 views

What are proper tests for analyzing choice between two options?

For surveys with the following responses, what are the appropriate statistical methods to analyze the data? The goal is to find which lists ultimately users prefer following several questions asking ...
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1answer
28 views

How to analyze within subjects count data?

Let's say we have three choices generated by three different algorithms shown to the users repeatedly, and users can choose one among three in several sessions. Therefore, each user has seen e.g., 12 ...
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2answers
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Unrealistic coefficients when comparing two count samples with glm poisson

I would like to test the significance of the difference in mean between two independent count samples. I'm doing this with a GLM poisson in R, as shown in the code below: ...
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1answer
68 views

Which statistical test should be used for comparing two discrete/count data?

Supposing that in an experiment there are two groups: Group A and Group B, each consisting of 30 participants. The participants are required to play a game for ten rounds. In each round, the ...
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Reverse causality in panel data with count outcome

I have panel data on several thousand individuals and I am trying to estimate a model to look at the effect of a variable $x_i$ on an outcome $y_i$. There is definitely a reverse causality ...
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How to handle big count data with huge orders of magnitude in GLMMs: center & scaling but than negative values are introduced?

I'm relatively new to GLMMs and so far only handled relative data. Now I'm trying to model if the abundance of a taxon is affected in the disease state (condition) when considering random effects like ...
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How to model the effect of categorical independent variable on count dependent variable?

I am working with panel data with a count dependent variable (no. of hospital visits, hospvisits) and categorical independent variable of interest (health status, healthstatus) with other mixed types ...
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VAR with different distributions: Does this model exists?

I would like to know if models like the one below exist/make sense and, if so, how they are called. \begin{equation} X_t \sim \mathcal{Pois} ( \lambda_t ) \\ \lambda_t = \mu_1 + \alpha_1 X_{t-1} + \...
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Poisson Multinominal Distribution?

I am aware of the Poisson Binomial Distribution describing the sum of independent-yet-not-identically-distributed binary variables, and its generalized version extending binary variables to variables ...
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Modelling catch rates: difference between Gamma and poisson distribution

I am confused about the difference between modelling counts (i.e. catch) using a poisson distribution with an offset (i.e. effort) and modelling catch per unit effort using a gamma(link=log) ...
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18 views

ANOVA for road accident data

I have a dataset showing the number of road accidents, persons killed and injured classified according to weather conditions(Sunny, Rainy, Foggy, Hail, Others) for 36 states. It kind of looks like the ...
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How to statistically model miscount rate?

I have a count-data of 3 different classes from 2 different sources (source A and source B). I know that both data sources contain miscounted data where some of class 1 elements are counted as class 2,...
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Why does my GLM show IRR and CI of 1

I'm running GLMs with occurrence data from a camera trap study. Cameras were set at various distances from a railway. I set up a poisson model and used the number of days the camera traps were active ...
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10 views

How can I generate seasonal count data that has two different expected values?

The motivation for my question is modelling changes in abundance of a species whose population is estimated from survey data. The challenge for me would be to see if ignoring a food indicator masks ...
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34 views

Interpreting gam.check plots Poisson family

I have a question regarding GAM models using count data and the Poisson family. Here the data set I am using. In the photos: model summary and plots generated using gam.check from the R package "...
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28 views

Ordinary Least Squares or Binomial Regression for count data with few trials

My general question is when should one use OLS and when binomial regression when the outcome is count data with a fixed upper limit. When the upper limit is large (like 1000) and most values are ...
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1answer
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Negative binomial regression analysis with crossed random effects

I face a challenge in running a model comprising (1) crossed random effects and (2) a zero-inflated negative binomial regression in R. In the study, I analyze interactions between organizations. ...
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10 views

Clustering count data with different columns weights

i would like to know if its possible to create cluster from a data with different pairs; I have count of aphids observations and count of observation with presence, then count of slugs observations ...
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Is the wilcoxon signed-rank test suitable for zero-inflated data?

I have data that look like this: (There's 285 entries) These are paired data, in that each line represents a single seal group that has been counted for entanglements using two different methods of ...
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1answer
57 views

Poisson regression with interaction

Im am trying to identify the effect of an antiviral compound. Therefore, I count the amount of vRNA spots per cell (=dependent variable) which is modelled as a logistic poisson regression. Each cell ...
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Linear regression - the use of count data [duplicate]

I hope that you do not mind helping me with this likely quite simple problem I am having. Can linear regression be used for count data? If not - do you know why do universities, as well as online ...
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29 views

Stationarity test for count data time series

can someone give me an overview of stationarity test for time series of count data? For instance, I would like to know if there exists a test similar to the Augmented Dickey Fuller or how this test ...
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16 views

How to effectively interpret probability statements

I'm looking for some equations that I can concretely use when trying to think about probabilities and how I should interpret statements or paragraphs of information relative to these. Here are a few ...
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8 views

Compare four groups with respect to a count variable

I have 4 periods of time (6-12,13-18,19-23,24-5). In each period of time a certain number of events occurs (for example in the period 6-12 123 patients became ill, in the period 13-18 231 patients ...
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Best method to analyse count data for several different categories

During a sustained attention task, participants were occasionally asked what they were thinking and to press a number indicating their current state of focus. Each instance asked the same question (&...
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1answer
17 views

OLS Consistency for Count Data?

Why would we choose Poisson / NB regression (GLM) over OLS for fitting count data? Is there a way to show that OLS estimator would lost it consistency and asymptotic normality for count data? I'm ...
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Is this the correct way to check if a certain count data follows an expected ratio through Bayesian methods?

In my current experiment, I am looking at the no. of pieces of chicken eaten vs that of bread by dogs. In a previous experiment we had done the same experiment on individual dogs. The data of that are ...
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28 views

Does distance correlation work for count data?

I'm considering using partial distance correlation to test for conditional independence in multivariate count data. However, I haven't been able to find any good sources that discuss whether (partial) ...
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74 views

Negative binomial assumptions and errors

I'm conducting a negative binomial regression in SPSS using the GLM menu and I'm receiving the following error message: Warnings: The Hessian matrix is singular. Some convergence criteria are not ...
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1answer
16 views

significance test to compare race-ethnicity among 4 groups

I am trying to figure out the right significance test to determine which of my 4 groups are most (1) non-hispanic white (2) non-hispanic black (3) hispanic or (4) other compared to other groups. In ...
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87 views

Problems with uniformity in residuals using DHARMA to check zero-inflated count glmm

very new to statistical modelling & have found lots of the existing questions and answers from this community hugely helpful. I'm running into some issues of my own now that I can't find answers ...
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14 views

Can I evaluate additive interaction for GLMM

I am currently running a GLMM (log-link function) examining the effect of two treatments on the instances of an arthropod. I seek to determine if there is additive interaction between the two ...
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196 views

What statistical test should I use with count data? [duplicate]

In my experiment, participants are shown 4 images (A, B, C, D) that they have to rate on a 5 point scale. So my data looks like this: particpant1: A 5, B 3, C 3, D 1 p2: A 4, B 3, C 2, D 4 p3: A 4, B ...
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How do I compare two count data and show that there is true difference between them through Bayesian statistics?

I have two categories : Protein and Carbohydrate denoting two type of food available in a setup. From Protein, 335 food pieces has been eaten from a total of 1095 pieces and from Carbohydrate, 70 food ...
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Appropriate statistical tests for very limited-range (0, 1, 2) count data?

I have some data from an experiment where participants from two different groups viewed a stimulus. There were 9 possible stimuli, distributed over 3 conditions (equivalent example: stimuli were all ...
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10 views

Why can negative binomial regression be used to model event rate/count data

It seems negative binomial regression can be used interchangeably with Poisson regression to model event rate? but I don't understand how it works. Poisson distribution is for count data. Poisson ...
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10 views

Defining ranges for random fluctuation in a count experiment with many output classes

a noob here. I am confused about many basic concepts. Let's say, I have a multilabel classifier with 3 output classes, and 5 measurements (let's assume one measurement for a month; so it's a time ...
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12 views

How should I compute confidence intervals for a proportional estimates of a Poisson count?

I'm developing an microbiological assay for enumerating defined mixtures of different bacterial strains that all have similar growth requirements and can't be distinguished by visual characteristics. ...
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18 views

How do I find the correlation between many different samples over multiple counts?

I'm new to this and I suspect my question isn't very difficult to answer, but I struggle with finding the answer. I have a dataset like this: This is just an example of the set-up I have. I'm simply ...
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48 views

Wilcoxon signed-rank test for count-proportions?

Let's say that I have several agents able to take action A or B, and I am interested in showing that taking action A is more likely. So I have a table that looks something like A B 10 2 14 6 ... .....
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1answer
35 views

Applying count models with rate responses

How do you apply count models to data which is count in nature, but a rate in reality? In such cases, r can handle this to a certain extent, depending on the model, but what is the correct way to ...
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quasi-poisson / Neg.Bin / Chi-square for analysing annual count data?

I'm interested in looking at annual trends. The numbers represent the total number of a particular animal species that have been counted in that year. We see a decreasing trend, and I would like to ...
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1answer
83 views

categories with count data, random and fixed effect in nested model

I am confused how to analyze this dataset in R: There are 2 islands, 2 sites were selected (nonrandom) per each island, 6 transects randomly were located on each site, then the number of corals was ...

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