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Questions tagged [count-data]

Count data are non-negative integers representing whole amounts.

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19 views

Proportion and rates from counts data - how to analyse? [on hold]

I'm quite new to statistics. I want to see if specific primate behaviours change after a health-screening. I watched some videos from before and after the screening and I recorded the length of time ...
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2answers
49 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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0answers
23 views

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
19 views

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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0answers
11 views

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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0answers
13 views

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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0answers
14 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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0answers
21 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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1answer
14 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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18 views

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
16 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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16 views

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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0answers
15 views

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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0answers
16 views

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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1answer
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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0answers
8 views

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
47 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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0answers
39 views

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
44 views

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
44 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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0answers
18 views

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 ...
2
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1answer
137 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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1answer
23 views

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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1answer
40 views

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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0answers
15 views

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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0answers
14 views

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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1answer
22 views

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, ...
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0answers
34 views

Is my data inappropriate for a zero-inflated regression model?

I am working with count data where I have an abundance of zeros for one of my categorical factors (Day). I have generated two models, p1 and m1, with zeroinfl() and ...
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0answers
35 views

finite mixture models with countreg and flexmix

I am testing making a finite mixture model for poisson and negative binomial on some artificial data using flexmix and countreg packages. Here is the core part of my small script: ...
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0answers
31 views

Differences between sample proportion within conditions and between conditions

please let me share with you some problems and ideas: I am conducting a research in which I have 6 types of answers (e.g. A, B, C, D, E, F) in 32 questions And two conditions (e.g. M, N). (each ...
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3answers
54 views

Modelling count data with time-series structure and predictors

I am doing an analysis of sales-data over a period of time (i.e. over a few years). Those sales-data are also dependent on some predictive variables (i.e. holiday, weekend, weather,...). The daily ...
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0answers
8 views

Modeling and testing for trends in hospital-surveillance (count, event) data

Intro Hi all, I'm working with hospital-based surveillance data. My peers and I are trained (loosely speaking) as frequentists. I'm mindful of the aphorism: Statistics: A subject which most ...
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1answer
58 views

Zero-inflated vs not Zero-inflated models for count data

I am analyzing a small dataset (d) of urinary track infections in a group of residents of a long-term care institution over a period of 6 months. The total number of patients was 29. I had used ...
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0answers
27 views

What model should I use? Time series count data grouped into provinces. R

I have daily observations on the count of a variable, with 1,000 daily observations across 15 different provinces, for a total of 15,000 observations. On certain days, there is an exposure, which may ...
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0answers
36 views

Are fitted.values available in pglm?

I am using the pglm function in R to fit a Poisson fixed-effects model. According to the documentation, the pglm object should have fitted.values. However, fitted.values(model-name) returns "NULL". ...
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1answer
38 views

Finding GLMMs that fit my count data for multiple datasets

I need some help finding a model that fits my data. I'm using GLMM's to test the effect of nitrogen level (numerical), species (two-level factor), and the interaction between these two variables, on ...
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0answers
27 views

R GLMM: How to deal with separation inflating standard errors in negative binomial regression (count data)

I'm comparing counts of individuals between different localities, and between two seasons (seas_wmo with levels dry and ...
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2answers
55 views

Poisson model appears overdispersed, but usual recommended approaches don't improve fit

Summary: I am trying to model some count data. I initially attempted to fit a poisson GLM, but diagnostics appear to indicate overdispersion. I have tried several different recommended remedies but ...
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0answers
16 views

Are median values numeric or ordinal?

I'm trying to set up the input data that I'd feed into my DL model and for the simplicity, I'm thinking of plugging in only the min/max/average values of the original data. (This is necessary for my ...
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2answers
69 views

GLMMs for count data with glmmTMB: random slopes specification, cross-level-interaction and strange results

folks, I recently found the great glmmTMB package which I hoped would help me with my models. My data are 60,000 facebook posts that are nested in 51 companies (i.e., the posts by these companies). ...
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0answers
25 views

Testing for non-zero values above and below the diagonal of a matrix

I have a $n\times n$ contingency matrix comparing count data (classification) of two procedures. I want to test for non-zero values above and below the diagonal (different classifications in both ...
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0answers
59 views

Why does pglm give different results thans log-plm?

I'm looking to regress a fixed-effects model on count data. My initial approach was to take the log of regressor on R's plm package. Then I found out about the pglm package, which enables general ...
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1answer
66 views

Asymmetric data analyses

I have a data set containing bacterial count values before treatment and after treatment. These data look asymmetric. Please advise me for a suitable statistical test to find if the introduction of ...
3
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1answer
43 views

Linear regression where some known records have a measurement error in dependent variable

I am modelling data where the dependent variable is the number of units of a certain product sold each month in each area. In all areas, the product is sold by a chain of shops 'A' and we have exact ...
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0answers
18 views

Which kind of diagnostic plots for count data? [duplicate]

I know that for an lm model is enough to run plot(model_lm) to get diagnostic plots. I am dealing with high-dimensional count ...
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0answers
19 views

Wald test for Poisson distributions

This question asks: $N_A$ and $N_B$ are variables of the counts of the number of events 'A' and events 'B' respectively. Those variables follow Poisson distributions with parameters $\lambda_A$...
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0answers
38 views

How do I model count data (Poisson regression) that has a seasonal pattern?

I'm rather new to R and poisson regression and have a few questions. I have count data of incidents per month, a couple years prior to an intervention and 1 year after. I want to use poisson ...
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0answers
17 views

Predict a disease with a compositionnal count data

I am trying to predict a disease (binomial response TRUE or FALSE) with count data (16S microbiom count) and I got one random effect (person's mother). Actually, im working on count's proportion ...
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1answer
33 views

Using `glm()` in R for correlated count data (data provided)

I have data from one group ($n = 25$) of subjects pre- and post- tested on an $15$-item dichotomously scored test (see below). Given that the data are from the same subjects (i.e., correlated), how ...
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0answers
29 views

Can Count data be used as predictors in a linear model [duplicate]

If someone is trying to predict a continuous measure (satisfaction) and their 2 predictors are discrete count data, can that person use a basic linear model (like lm...