Questions tagged [count-data]

Count data are non-negative integers representing whole amounts.

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rate of counting of the sensors

Let's assume we have system of detector which is composed of 7 sensors, which can identify particles. Let's assume we have 70000 selected events, where total number of hits collected from the sensors ...
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36 views

How to model count data in which events are not independent

I have data on the number of hospitalizations over one year in patients with chronic obstructive pulmonary disease, and I need to estimate the difference in the number of hospitalization between two ...
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42 views

Response is count and the first explanatory is binary second is continuous. Which GLM should I use?

So I've got a response variable with count data e.g. number of species found and two explanatory. The first is a treatment I did or did not applied -> Yes or No, so binary. My second explanatory would ...
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20 views

One- vs two-sided credible interval for Poisson process with all zero counts

In a related question, I asked about a confidence interval for the estimate of the mean of 50 observations of a Poisson random variable, for which all 50 observations had a count of zero. In the ...
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Standardizing predictors for Neg Binom Regression

tl;dr: If I include an interaction term in Negative Binomial Regression, should I standardize the predictors? I am analyzing a very large dataset (over 60 million observations) that has the following ...
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50 views

how to run a two way ANOVA in excel on summary data: counts of consumers

I have a table of counts of consumers, and I would like to run a 2-way ANOVA on them. There are two factors, year and age-group. Please see the following table of data. Although I usually have ...
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Count Analysis - How to analyze the Impact of a Predictor

Say you have data as shown below and the data represents Incidents of a certain type at a Toll Plaza. The incident count is directly related to the Vehicles Per Day (VPD), so you can calculate the ...
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Means centralization, is it a thing?

Assume a dataset of counts in distances (1, 2, 5, and 10) to a point from three independent samples (a, f, and ...
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1answer
74 views

Confidence intervals for the mean of a sample of counts

I'm sure the answer to this question is obvious, but I can't seem to find it! How do you calculate the confidence interval around the mean of a sample of counts? I've made an example below in R, ...
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Time series Count-data forecasting in R [closed]

I have sales data shows the number of units sold (so it is a count data). I am evaluating the following models: the lightgbm Count Time Series Following Generalised Linear Models (R tscount library) ...
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From multiple Bayesian BetaBinomial bandits models, to logistic regression

Suppose I have a single categorical predictor $X_1$ with K>2 levels, and a binary outcome Y. We have two objectives, in order of priority: Identify if there is level $k$ in $X_1$ that significantly ...
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Poisson regression for count data that is not Poisson distributed?

Is it true that Poisson regression is used to model count data? But not all count data follow a Poisson distribution? Then you can still use Poisson regression in that case?
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Check if dropout rates are independent for an interaction of two independent variables (one with a large amount of levels)

I am trying to analyse dropout rates in an experiment, but there are multiple issues which collide, and I don't know how to deal with them as a whole. First, find a list of those issues. Below, see a ...
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Pearson Goodness-of-Fit Test

I am trying to compute the Pearson-Goodness-of-fit statistic for Count data to see if the mean and variance are correctly specified. I am using example data from Deb and Trivedi downloaded here: https:...
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Variable selection in zero-inflation models

I am trying to understand how to perform model comparison between different count models. In this example the author performs a zero-inflated poisson model testing the effect of number of people in a ...
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1answer
25 views

How to test mean differences in proportions that are dependent

I have an experimental setup where I have allowed groups consisting of about 50 animals to select between two environmental conditions. I.e. animals had the possibility to move between the two ...
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Count Data and Relationships

I am new and it was suggested I migrate a question I have over at StackOverflow. I am editing the question to hopefully make the stats question easy to understand (without the noise of code ^_^ ) ...
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1answer
60 views

Computing different types of negative binomial regression

I want to compare different Count Data Models. How does one compute NEGBIN type I and NEGBIN type II in R? Which model is estimated by glm.nb()? Thanks in advance
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have many error likelihoods, how to combine to get a confidence or p value?

I'm working in bioinformatics and its been a long time since I dusted on my statistics. Basically I'm working on variant calling which amounts to sequencing a large number of sequence reads and ...
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Why do negative binomial regression coefficients differ by level of data stratification and coefficients from Poisson models do not?

I'm trying to understand why regression coefficients from negative binomial models are sensitive to the level of stratification of the data and regression coefficients from Poisson models are not. ...
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Choosing the appropriate test to use when analyzing categorical count data

I am analyzing data that compares responses to various questions across a variety of demographics. I want to see how the count of each response varies by each demographic group. The most basic test to ...
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count data model with capped response variable

I'm trying to predict the total number of Olympic medals won by a country in the summer Olympics games. I have data from 2000 to 2012 relating to the country gdp, population, number of athletes sent, ...
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1answer
64 views

Kruskal-Wallis and Negative binomial regression do not agree

I am comparing the number of broods made by dung beetles (Brood_Number) across three temperature treatments (Temp_Offset, a 3 ...
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21 views

Predicting vector of counts

I was wondering if there are any models that are similar to Poisson regression, but instead of having 1 count as the target, there is a vector of counts as the target. For example: Typical Poisson ...
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2answers
60 views

Data analysis for counts

What would be the best data analysis to use for the following data? I was thinking of using the Wilcoxin ranked sum but there are so many ties. I have two independent groups and I am just looking to ...
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Dynamic poisson-time series regression

Basically, my question is similar to Time series dynamic poisson regression, yet I didn't get any clue by its answer. I'm modeling dengue incidents with GLM (poisson regression; because the response ...
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1answer
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Regression with count data as an independent variable

I want to understand the appropriate way to regress a duration variable on a count variable. For instance: I have data on turn around time of a process in a hospital ward. The ward admits patients ...
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Overdispersion under different longitudinal constraints

I have panel data (police districts observed across many months) and I am modeling a count outcome. Fitting a Poisson model (simple pre/post comparison with 6 months of data) results in significantly ...
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Zero-inflated Poisson regression with `unit` and `time` fixed effects (Application in R)

In much need of some assistance. My question concerns the conceptualization of zero-inflated Poisson regression in a two-way fixed-effects settings. I have crime data and my outcome is 'count' ...
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31 views

Random Forest classification based on count data as features

I'm implementing a Random Forest for binary classification and I use a combination of features. Very important features are based on count statistics. I'll give an explanation: for every instance of ...
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28 views

How should I determine the CI of my classifier counts?(i.e. 95% confidence at least 30 objects are present)

I have built a classifier that detects a disease based on the presence of certain particles and the amount of said particles. An uninfected person would have 0, light infection is less than 50 ...
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61 views

How to apply INAR model to a simple time series model in Python

As a course project for Time Series Analysis, I used ARIMA for a very simple model - (Analyzing number of deaths in each episode of game of thrones and forecasting the number of deaths in the final ...
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How to choose number of lags i Poisson regression?

I'm working with a dataset containing game data from one season in NHL. My goal is to create a Poisson regression model that consist of the most important variables that explain why a player produces ...
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1answer
32 views

Scoring rules for count models on: training data vs. validation data

In order to evaluate and compare count models (e.g. Poisson regression), we can calculate scoring rules (e.g. Brier Score, Dawid-Sebastiani score, etc.) which are explained here: Error metrics for ...
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Overdispersion tests from DHARMa and sjstats: conflicting results?

I ran some models for my count data, and did some diagnostics to check for overdispersion. Here is a dharma graph, which as I understand, indicates no overdispersion. And this is the result I get ...
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Modeling count data (left skewed, underdispersed, right-censored)

I am seeking to model a count response variable-- number of times subject enacted a compensatory behavioral strategy-- as a function of cognitive and behavioral symptomatology, which are both ...
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How to compute the expected number of events in the following conditional renewal process?

I have a stochastic point process with event times $\{x_1, x_2, ...\} $ and I want to compute the expected number of events $n(T)$ over the interval $[0,T]$. The point process is generated as follows: ...
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36 views

Variables measured on two different scales

I am dealing with three continuous predictor variables (corolla tube width, corolla tubedepth, corolla inclination) and a discontinuous response variable (counts of bee visits). I am confused on how ...
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Trouble interpreting GLM Quasi-poisson

I'm doing a count model on the rate of exonerations over prison admissions before and after 1992. I understand that Year > 1992 is the change in intercept post-...
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1answer
53 views

Best approach for time series

What approach would be best for time series that tracked user generate some events (activitie is file creation - from 0 files per day - 18 files per day ). I determined that number of events per day ...
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Adjusting for clustering and overdispersion in count models

My question is specific to the estimation of glm's and correcting for 'clustering' in a quasi-experiment (difference-in-differences). My outcome is counts of crimes....
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1answer
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How should I model this data?

I need to use R studio to model the following problem: According to the Independent newspaper (London, March 8, 1994), the Metropolitan Police in London reported 30,475 people as missing in the year ...
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1answer
116 views

DHARMa diagnostics: testDispersion and testZeroInflation interpretation

I have been analyzing count data using Poisson distribution in glmmTMB, and just ran some DHARMA diagnostics. However, there don't seem to be a lot of help online on how to interpret the results. Does ...
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When to use PCA vs LDS vs nMDS for microbiota dataset?

I'm trying to understand the certain situations in which you would use the 3 above ordinance/rank tests over the other in terms of microbiota count data. Typically, I have been told to use nMDS over ...
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1answer
160 views

Analysis of count data with percentages

for my master thesis I count and identify sediment grains. In total I have 82 samples from 3 different gravity cores. I divided the sediment components in 11 groups (Quarz, Mica, Opaque, Aggregate, ...
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Statistical specification for a Regression with continuous finite range count like data

I am interested in explaining what kind of personal characteristics and work environment variables are associated with sickness absenteeism. My dependent variable is the total number of days a given ...
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I have derived the Mean and Variance of a truncated Poisson distribution. Does this show under-, equi-, or overdispersion?

The density looks like this: $P(Y=y) = \frac{e^{-\lambda} \lambda^y}{y!(1-e^{-\lambda})}$. I derived the mean and variance and got this: $$\operatorname E(Y) = \frac{\lambda}{1-e^{-\lambda}}$$ $$ \...
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Comparison of paired count data between two treatment periods with different length of follow-up

I am currently using SAS 9.4 to carry out a retrospective analysis of patients who switched from drug A to drug B. I am interested in assessing the hospitalization counts before and after switch to ...
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Is a single count data point significantly different from a set of reference count data

I have counted the number of occurrences of protein domains in the proteomes of 16 different insect species, 1 focal vs 15 reference species. For each of the ~4700 protein domains in my data, I have a ...
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How can I compare how significant is the difference between three or more distributions of count data?

I am researching whether software developers use different numbers of communication channels when performing different activities. Therefore, I would like to know whether, depending on the activity, ...