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Questions tagged [count-data]

Count data are non-negative integers representing whole amounts.

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Poisson two-way ANOVA test for Before and After treatment (including a control)

I am having trouble to determine what type of test to use in this experimental design: My data is like this: I got 10 treatment sites and 4 control sites I got replicates for each treatment and ...
Sergio Nolazco's user avatar
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0 answers
69 views

How to do rarefaction analysis for sample-based abundance data?

I would like to compare plant richness of different forest stands via rarefaction. The data is collected in a plot-based manner. I set 4 equal-sized plots in each stand, counted all plant individuals ...
Sitta's user avatar
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0 answers
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Multiple poisson regression with one count and one continuous IV?

As one of my independent variables is a continuous variable and the other is a count variable, would I still be able to do a multiple Poisson regression?
Ally's user avatar
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5 votes
2 answers
334 views

Standard negative binomial regression when counts are mainly zeros?

This question must have been asked many times before but I can't find an answer. I'm getting very confused about when to use a zero-inflated negative binomial regression vs standard negative binomial ...
Picapica's user avatar
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4 votes
1 answer
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When to choose GAM over GLMM and how to include random effect into GAM

This is a follow-up question to this question. Here is a description of the dataset: the outcome variable is the number of contacts per participant for two periods before lockdown and under lockdown. ...
Chao's user avatar
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3 votes
1 answer
220 views

Can I include a variable related to the outcome variable into statistical analysis?

My research question is about the contact patterns during the pandemic and what characteristics of people who contacted more person during the national lock down. The outcome variable is a variable ...
Chao's user avatar
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1 vote
1 answer
35 views

Linear models to compare SNP categories between patients

I have 8 patients (GROUP: 3 healthy, 5 disease). For each patient, I determined single nucleotide polymorphisms (SNPs) and annotated the effect of the SNPs (EFFECT_CATEGORY). Each SNP (~3000 per ...
BackFish's user avatar
0 votes
2 answers
45 views

Negative log-likelihood, high BIC, high R-squared, low error, using a difference-in-differences (DiD) methodology [closed]

I am trying to see the impact of Brexit on UK imports. My dependent variable are EU exports to the rest of world. I have monthly data from 2013 to 2023, also data is in billions of GBP. When I do ...
rea123's user avatar
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6 votes
2 answers
262 views

Count predictor and binary outcome

Is a binary logistic regression the best approach when I have a count predictor and a binary outcome? Can I apply a multiple binary logistic regression model if I have more than 1 predictor that is a ...
stephan_phd's user avatar
0 votes
1 answer
22 views

Underdispersion handled with negative binomial distribution? [duplicate]

To get a more flexible model than Poisson regression, one can choose the negative binomial distribution instead for modeling with $E[y] = \mu$ and $Var(y) = \mu + \frac{1}{ \theta} \mu^2$. As a ...
Marlon Brando's user avatar
1 vote
2 answers
41 views

Calculate combined confidence interval of two variables in a negative binomial model (in R) [closed]

I have a multivariable negative binomial model in R for which I want to combine two variables: Variable 1: binary variable (no/yes) Variable 2: continuous variable (0-3) I want to calculate ...
femkev's user avatar
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6 votes
3 answers
281 views

dispersion of a negative binomial model

In R's, glm.nb summary, it says dispersion parameter $\phi$ is set to 1. When the model is $Y \sim \text{Negbin}(\mu,\theta)$ where $E(Y)=\mu$ and $V(Y)=\mu+\mu^2/\...
quibble's user avatar
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1 vote
0 answers
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Cumulative Residual Plots for GLM Goodness-of-Fit Tests

I wanted to ask about the cumulative residuals (CURE) plots for testing the goodness of fit test for negative binomial regression. CURE plot has been a standard in traffic crash frequency modeling for ...
Barton's user avatar
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0 answers
29 views

Which log-likelihood is to be maximized for left-truncated count data?

What is to be done, if the count data is missing the counts on the zeros (i.e. left truncated data)? Say one wants to estimate a Poisson regression and the goal is to derive the log-likelihood to be ...
Marlon Brando's user avatar
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19 views

getting incidence rates from IRR using zero-inflated poisson regression

my data looks like this: and so i used zero-inflated poisson regression model to model events (e.g., hospitalization for a specific condition). ...
Yuliya Deni Krushni Nikolayeva's user avatar
1 vote
0 answers
26 views

Count data with time-varying covariates

One way to model count data is to simply count up the number of events as the outcome with an offset of observation time if this varies between people. I presume it's also possible to model count data ...
LucaS's user avatar
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How to model heterogenenous count data?

I have been trying different models to model highly variable count data (mean 8.5, variance 144.3), that is grouped by participant (each participant took between 4 and 16 tests). Within each ...
David's user avatar
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2 votes
1 answer
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When to include random-effects in zero-inflation model component?

Is it appropriate to specify random-effects (RE) in zero-inflation (ZI) component of the model? My intuition is that whatever RE is appropriate for main component should be appropriate for ZI ...
Suhas Bharadwaj's user avatar
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0 answers
13 views

Finding Main Effects from Negative Binomial Regression with Interactions

I have used a Negative Binomial Model for count data. I have 2 predictors. Age (2 or 4), Height ( short, medium, tall). In my model I have Age + Height + Age * Height. For theoretical reasons, my ...
Alexis2014's user avatar
0 votes
1 answer
16 views

How can I justify using counts plus offset in a Poisson or NB model instead of "percent of total"?

I have count data that is part of a whole. It's not compositional, because the other parts of the whole aren't of interest. I could analyze it as a "percent", but I would rather do it as ...
Bryan's user avatar
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2 votes
2 answers
46 views

Help with choosing stats test for bird count data

I am a university student working on analyzing some data, and am looking for a little bit of statistics help and guidance. Data overview: I am doing a research project on birds, and am trying to ...
user17349598's user avatar
0 votes
1 answer
57 views

Difference between zero-inflated model and zero-altered model

Could someone explain what assumptions I am making (perhaps implicitly) when I specify family = nbinom2() versus ...
Suhas Bharadwaj's user avatar
0 votes
0 answers
15 views

Am I Doing Things Right? / negative binomial test

I have a dataset consisting of social media comments about a particular context from 1999 to 2024.The topic titles of the comments were annotated into two categorial variables = 0 and 1. I am aiming ...
berk's user avatar
  • 1
0 votes
1 answer
42 views

Twitter controversy - adjusting for population for counts of Tweets by country

There's some controversy in Ireland at the moment surrounding the number of international profiles sending tweets using a specific hashtag. I came across some people arguing about whether or not the ...
adkane's user avatar
  • 1,021
0 votes
1 answer
64 views

Transforming count data for NMDS?

I am looking at species count data. Due to large counts of certain species, I initially fourth root transformed the data. I am using Bray-Curtis distance measurement. However when using vegan::metaMDS,...
user390865's user avatar
0 votes
0 answers
7 views

Should data be transformed for NMDS? [duplicate]

I am looking at species count data. Due to large counts of certain species, I initially fourth root transformed the data. However when using vegan::metaMDS-Bray Curtis distance, the stress value for ...
user390865's user avatar
0 votes
0 answers
15 views

Combining percentages to estimate new percentage

I am trying to estimate the proportion of the true freshman cohort (first-time, full-time, degree-seeking) who declared an undergraduate-level college major in their first year of college by their ...
Robert's user avatar
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2 votes
1 answer
25 views

Count Data Dependent Variable

Just a quick one - I am planning on running a negative binomial distribution to test the time spent at the gym in a week, against a series of controls. I just wanted to double check - would the number ...
Vito's user avatar
  • 123
0 votes
1 answer
46 views

Statistical test for frequency counts?

I have data of customer purchases over time. Certain clusters of purchases tend to occur together within a short timeframe for each customer. One customer can have multiple clusters of purchases. I ...
Alis's user avatar
  • 1
4 votes
1 answer
54 views

Modeling no-show rates of attendees in R

I'm trying to determine to what extent the no-show rate of registered candidates to a (past) event is dependent on the weekday that the event was hosted on. Given a number of past events that have ...
Marco W.'s user avatar
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0 answers
31 views

Is this suitable for Negative Binomial Regression?

I am using SPSS to run a negative binomial regression for my research project. My dependent variable is 'Number of Days Went to the Gym' in a week, and my independent variable is income (along with a ...
Vito's user avatar
  • 123
4 votes
1 answer
164 views

Running a Negative Binomial Regression with Overdispersion

I am not an expert on SPSS but have been developing my skills and believe I should run a negative binomial regression on my data, though I am not certain. I am testing the number of days people go ...
Vito's user avatar
  • 123
0 votes
0 answers
10 views

Modelling count from frequency

I have an empirically derived frequency curve. From the curve, I aim to model counts per unit time. The x-axis is diameter, and the y-axis the likelihood of observing the diameter per one year. I ...
Eron Raines's user avatar
6 votes
1 answer
108 views

Small Sample Sizes and Zero Inflated Count Data in R

I am working to produce a model in R for seed germination count data with lots of zeros (around 50% of the 264 total observations). The purpose is to determine the effect treatments have on plant ...
newspice's user avatar
1 vote
1 answer
44 views

Performing "exact" G-tests in R with contingency table samples using `r2dtable` [closed]

I am interested in performing the "exact" versions of G-tests of independence in R with nonparametric table enumeration after having been told that this could help with achieving more ...
potpie's user avatar
  • 63
2 votes
1 answer
66 views

Can I use month variables to capture linear increases and seasonal effects in the same model?

I have count data (numbers of articles published) that I want to model as a function of time and location. I suspect there's an increasing linear effect with time but also a seasonal boost in the ...
adkane's user avatar
  • 1,021
1 vote
1 answer
39 views

Count data and proportion covariates: best practices

I'm working with spatial data and I have the following log-linear model for count data. Let $y \sim Poisson(\lambda_{i})$ such that $$ \log \lambda_{i} = \text{x}_i^\top\beta_{} + \epsilon_{i} $$ such ...
BelwarDissengulp's user avatar
0 votes
0 answers
15 views

Predictors of Poisson or Negative Binomial Regression of LMM or GLMM

Just wondered if statistically it is wrong to have count data as a predictor (not confounders) of a Poisson or Negative Binomial Regression of LMM or GLMM? So far, I have seen continuous or ...
Esario Daguman's user avatar
0 votes
0 answers
20 views

Incomplete formula for the glm negative binomial

My data is about the number of insects that go to treatment 1 or treatment 2, and I have the factor place, with four levels (places). Each place has a treatment and ...
Yahana Aparicio's user avatar
1 vote
2 answers
140 views

Chi square test of independence with year as a categorical variable?

I suppose that this is a very simple question, and I have just now recently started doing stats. I am working on a dataset with count data relating to discontinuation/continuation of a specific ...
Mukilan S C's user avatar
2 votes
0 answers
35 views

Comparing results from Poisson regressions

I have a dataset with count data (y variable), one primary variable of interest (factor denoted x_1), and several variables I wish to control for (factor and numeric denoted x_i). Say, y is the number ...
steve's user avatar
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2 votes
0 answers
60 views

Error metric for regression of count data: Poisson Deviance or Mean Square Error?

I would like to understand what difference it makes, if I use, for example, either Mean Square Error or Poisson Deviance as error metric/loss function for a regression of count data. Are there any a-...
g g's user avatar
  • 2,708
5 votes
1 answer
121 views

Percentage of females as a regressor in count model with population as offset - interpretation?

I am using a hurdle model (binomial logit for the zero counts, truncated Poisson for the positive counts) to study the effects of demographic (and other) variables on the adoption of private air-...
Giovanna's user avatar
2 votes
1 answer
38 views

Using Anova with count variables

I am testing a hypothesis where my independent variables (Xs) are count data ranging from 0 to 10. My dependent variables (Ys) are also count data, ranging from 0 to 10. I am expecting to see an ...
NutellaMonster's user avatar
1 vote
0 answers
27 views

Optimal three parameter variable stabilizing transformation of a Poisson

In the paper: "On the classical choice of variance stabilizing transformations and an application for a Poisson variate", Shaul K. Bar-Lev and Peter Enis give an optimal two parameter ...
cfp's user avatar
  • 535
3 votes
1 answer
83 views

Dependent variables are count variable with an upper bound

I need to test some hypotheses for a social sciences dissertation. In my description below, I refer to the independent as the Xs and the dependent variables as the Ys. I am expecting a straight linear ...
NutellaMonster's user avatar
4 votes
1 answer
279 views

Linear regression when independent variable are count data

In my upcoming social sciences dissertation, I am delving into testing hypotheses that explore the relationship between certain variables. In my framework, I've categorized these variables into two ...
NutellaMonster's user avatar
4 votes
1 answer
164 views

Dependent variable is a bounded between 0 and 1

I need to test some hypotheses for a social sciences dissertation. In my description below, I refer to the independent as the Xs and the dependent variables as the Ys. I have jotted down what models/...
NutellaMonster's user avatar
4 votes
1 answer
29 views

Count data multiple groups. How to define if particular groups are enriched for tumor counts or not?

I have counts (from multiple cell types) here only tumor is shown. I want to quantitatively define the clusters below as tumor rich/tumor poor based on tumor count. Tumor count represents no. of tumor ...
Saad Khan's user avatar
  • 101
1 vote
0 answers
39 views

How do I transform this regression?

I am researching bladderwrack and whether they can adjust their amount of bladders (small inflated bags of air that develop on their skin) depending on how wave-exposed the surroundings are. Hence I'...
Telefondemonen_se's user avatar

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