Questions tagged [count-data]

Count data are non-negative integers representing whole amounts.

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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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Help in understanding the raw data behind a Poisson regression and its log transformation [closed]

I would appreciate a sanity question. I have two questions concerning my count data: Question 1 I've just finished reading this article: https://www.theanalysisfactor.com/regression-models-for-count-...
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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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Data visualisation and exploration for count data

I have a fairly large data set with ~1000 observations about residents of an area. This is a dataset consisting of 15 variables, of various types (eg age, sex, income, years spent living in the area ...
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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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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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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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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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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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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
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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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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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1answer
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Analyzing animal behavioural data in R Studio (GLMM) and struggling to understand how to set up the model

I'm trying to determine whether there was any differences in behaviour (count data, frequency per 30 minute observations, categorized into 5 categories [e.g., affiliative, agonistic, etc.]) of a ...
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Applicability of Gaussian error propagation for poissonian distributed data

my question is whether there is an analytical expression for the error on a function where the variables of the function all follow a Poisson distribution? I will give a coded example with ...
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Are Poisson regression with robust SEs and Negative Binomial regression NB1 acceptable when the outcome is the sum of dependent Poisson distributions?

The sum of two variables $X_1$ and $X_2$ with Poisson distribution that are not independent has a Hermite distribution. It seems to me, however, that such distribution is not very popular (I only ...
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Is traditional negative binomial regression robust to model misspecification or not?

By "traditional" NBR I mean NB2, i.e. the one modeling variance as a quadratic function of the mean, with the formula: $Var(Y)=E[Y]*(1+\alpha*E[Y])$. I have found contrasting statements in ...
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How to evaluate overfitting in GLMMs usnig R

I am using glmmTMB in r to model count data. I use poison and negative binomial error distributions. If I add one more predictor to my models I end up having convergence problems. I would like to ...
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Which statistical test with count data in SPSS?

I am trying to figure out which statistical test to use for a set of field count data. Fish are counted for five different reef types during 10 different surveys. Each reef type is counted twice for ...
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25 views

How to test for Zero-Inflation in count data?

I have a data with some zeros and I want to test if the zeros are inflated. Is there a way I can directly test it? There is a similar question, but I don't think I find a solution. I model this with ...
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Poisson, Negative Binomial, and zero-inflated Poisson and Negative Binomial within a multilevel modeling context [closed]

I’m analyzing count data (e.g., number of students with suspensions), and the outcomes also have many 0s. The data are also nested (schools within districts). I’m familiar with using Poisson and ...
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1answer
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Hypothesis testing for count variables in (possibly) nested data

I am analyzing word usage in multiple two-person conversations between students and teachers, and want to test whether the usage of a given word differs between the two speaker roles. My interactions ...
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1answer
28 views

What statistical analysis to run for count data?

I have 10 storages, each has 10000 units. A technical problem has been found in 2 storages, that might leads to an increase in the number of defective units. Basically, I want to compare the number of ...
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Performing GLMM on community data with manyglm

I'm analysing some arthropod community data with generalised linear mixed models (GLMMs), using the manyglm function from the mvabund package. This data has arthropods sampled from multiple trees in ...
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Terminology for exponentiated coefficients from GLMs without a time offset

In GLM count models with offsets for time, I know that the exponentiated coefficient is commonly referred to as an incidence rate ratio, which makes sense given that the quantity being modeled is a ...
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Statistical test for pair-wise comparisons of 36 different counts

I have 36 different population types that vary in combinations of three parameters (s, g, d). g and g has 3 discreet variations (0.2, 0.8, 0.95 and 10, 100, 500 respectively) and d has 4 (1.0, 0, 0.1, ...
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Negative binomial posterior predictive for overdispersed counts

I've currently been working with the posterior predictive distributions of count data using the Poisson likelihood, but now need to extend that to handle over-dispersed counts. Naturally I thought of ...
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58 views

Can't transform data into a normal distribution

We have data on the counts of a certain disease in our city. We're trying to see if there's a difference between the male and female instances of it. We have decided to t-test for this, but both of ...
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How to determine corelation between four count type data in R?

Basically, using R, we measured number of (herbivore, herbivore, carnivore and plants) four factors, so count data, that is all i have. Two measurements so year 0 and year 1 in different locations - ...
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22 views

Cutoff for a poisson-gaussian mixture model

I have count data that is bounded on one side at zero (see image). It is bimodal and I think it results from two different processes. I would like to fit a poisson distribution around the hump around ...
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What statistical test to use when both predictor and response are count data? [duplicate]

I'm running a statistical test on a model that I made in scratch. It involves a bear catching salmon. The predictor variable is how many salmon can the bear eat before it needs to stop for a while and ...
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Experimental Design for count data in a (4X2) Factorial with replication

I am in need of help choosing a statistical model for count data with experimental replication. The Experiment (4 X 2 Factorial experimental design) -Factor A = Control, Low, Medium, High. -Factor B = ...
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Analysing mean count data for correlation

I am trying to find out if count data is correlated with the location it occurs in. The data includes multiple subjects from a group of locations and each subject has 0 to many occurrences of the ...
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13 views

Statistical test for comparison of counts for 2 groups where requirements for Chi-Square test are not met

I would like to compare overall codon counts in the yeast genome with codon counts from an individual sequence. The totals for the 2 groups are not the same. I cannot use a chi-square test, since when ...
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29 views

Test for equality of distributions for paired (overdispersed) count data

I have overdispersed count data with an excess of zeros. I split them into a training and a test set and tried to reconstruct its distribution through the training set. I then sampled from these ...
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1answer
48 views

Prediction after Hurdle model

I am estimating the effect of future expectations of profits on hospital admissions and days of hospital stays. The situation is as follows: Hospitals are paid a fixed tariff for the first x number of ...
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How to check for heterogeneity over time and location for rate data

I have data that consists of different locations, with repeated observations over time, of counts (and a denominator to make a rate). eg ...
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1answer
49 views

Count data with largely varying sample sizes. Can I get anything from the data?

I only have categorical data, between two groups, with more than three categories per data set. Here are some actual examples of the data: Comparing (https://www.strawpoll.me/4380945/r) to (https://...
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1answer
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What is the specific issue with using count data for ANOVA tests

I'm running a study with a between-groups component and a within-groups component, with a predictor that is count data. I was planning on using split-plot ANOVA to analyze this, but after seeing lots ...
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1answer
49 views

Statistical analysis of paired count data

I have conducted an experiment where groups of animals were allowed to select between different substrates. I had a tank with four different substrates (increasing in complexity from one side of the ...
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65 views

Correlation between count sparse data?

Having a matrix size 1000x500. Each row vector is a count of occurrences of events, the vector can be sparse, but what I am interested in is the similarity between row vectors. Let's say that they are ...
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31 views

Which model if poisson-model is overfitting zeros?

I want to fit a multilevel-model with a count dependent-variable. I checked for zero-inflation (underfitting of zeros) in the dependent variable, which wasn't the case. However, the test for zero-...
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Regression or statistical test for change in counts after a treatment

I am seeking suggestions for suitable regression or statistical tests to measure the effect of a treatment in counts (or proportions), when a control group is not available. Let's say an event takes ...
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1answer
93 views

How to convert a negative binomial regression coefficient to an alternative effect size?

I am conducting a meta-analysis and the effect sizes are mostly Cohen's d or log odds ratios. However, a few of the effect sizes are regression coefficients obtained from negative binomial regressions....
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1answer
200 views

Delaunay triangulation, with connected coloring

Let suppose I have a Delaunay triangulation with $n$ triangles, and K distinct colours. I want to color each triangle such that if I start from one triangle with color k, i can reach all triangles ...
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Intercept of negative binomial Regression with weighted effect coded variables does not equal sample mean

I am facing a really puzzling issue. I am analysing data of employees' absentism because of illness during four months with a negative binomial GLMM with the employees' department as a random effect. ...
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How does one typically present negative-binomial hurdle model results in a table?

Context of the data: I have over-dispersed counts of an insect on leaves. These leaf counts come from two groups: treated and untreated. I was initially reluctant to simply express the treatment ...
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32 views

root square vs log data transformation vs negative binomial model

I'm doing a statistical analysis on a survey based on a likert scale and I start by saying that I'm not an expert of statistics. What I want to understand is if there are significant differences in ...
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21 views

CLPM with count data in lavaan

I am hoping to run a crossed-lagged model with two timepoints and two variables. One variable is continuous, and the other is symptom count (zero-inflated). What would be the best approach for dealing ...

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