# Questions tagged [negative-binomial-distribution]

A discrete, univariate distribution modelling the number of ${\rm Bernoulli}(p)$ trial successes until a specified number of failures occur.

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### 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 ...
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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. ...
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### Covariance of multivariate negative binomial with random effects

I am fitting a negative binomial-2 regression model where there is a multivariate normal random effects term. I would like to find an equation for the covariance of two outcomes. In "the ...
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### Continuous mixture distribution

I am currently working on the derivation of the negative binomial distribution as a result of a continuous mixture of Poisson and Gamma distribution for regression purposes. To obtain the entire ...
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### glmmTMB ZINB model non-convergence

I am looking for help with fitting a ZINB model with mixed-effects. The model which I intend to fit contains a random-intercept (three variables/terms denoting the nested, hierarchical group structure)...
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### 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 ...
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### Negative Binomial SPSS Error

I was running a negative binomial regression in SPSS and received the following message: The maximum number of step-halvings was reached but the log-likelihood value cannot be further improved. Output ...
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### 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 ...
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### SPSS R^2 for Negative Binomial

I am running a negative binomial regression in SPSS and wondered if there is any way to display R^2 statistics, as would be the case if binary/linear regression was conducted?
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### 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 ...
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### Missing predictor variable in GLMM.nb outcome

After running the model: ...
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### GLMM with negative binomial- narrowing down variables & choosing a model

I'll start by saying apologies for perhaps not wording things correctly, as stats is not my first language (lol). Please let me know if there is any other info I need to provide to make this easier to ...
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### Choosing between Negative Binomial, Zero-Truncated NB, and NB with Arithmetically Altered Outcome (SAS)

I am modeling longitudinal Days of Pill Supply with predictors Number of Rx's and Patient Race. I was not able to use linear regression (proc reg or proc glm) because of heteroscedastic residuals, so ...
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### Multinomial distribution approach as negative binomial?

I was asked to solve a problem, following the multinomial distribution (if you think is the correct approach, which I actually think it is). I paste the whole problem just in case I am approaching, ...
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### Post-hoc tests of interaction for a negative binomial regression with survey weights?

I ran a negative binomial regression with survey weights using the R package survey and the function svyglm() and observed a ...
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### Constructing a one-sided hypothesis test for joint probabilties of negative binomial distributions

I am conducting research on Codling moth population/trap capture models. The end goal is to have a hypothesis testing model that will provide whether or not (at some significance level $\alpha$) the ...
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### NB regression and LAG variable X

I'm doing a time series analysis, and I want to fit a negative binomial regression model. I did a GRANGER analysis that told me that the LAG of X explains Y better than the LAG of Y. And in the ...
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### How do I work out the significance of main effects in negative binomial models with more than two factors?

I am trying to look at how the number of events X is affected by the three factors A (4 levels), B (2 levels) and C (2 levels) using a negative binomial model as follows: ...
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### Equivalent of R-squared in negative binomial regression

In my study, I experiment with fixed and mixed effects negative binomial regression to my data (in R) as the response variable is a count variable. I have read somewhere that unlike in the case of ...
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### Requirements for negative binomial regression

In my study, I experiment with fixed and mixed effects negative binomial regression to my data (in R) as the response variable is a count variable. Normally I should use Poisson regression but (and ...
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### Is it possible to run a zero-inflated negative binomial model with complete separation? [duplicate]

I am trying to analyze how the number of events Y is influenced by three factors A (4 levels), B (2 levels) and C (2 levels) and the interactions between the three. Initially trying a poisson ...
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### Predictive capacities of Generalized Linear Models and significance

I have the following data ...
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### 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 ...
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### Taking the limit of a Beta Distribution to yield the Gamma Distribution

The Poisson Distribution may be obtained from the Binomial Distribution by keeping $\lambda = np$ fixed and taking the limit as $n \rightarrow \infty$. Similarly, the Gamma Distribution may be ...
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### Clustering and segmented regression interrupted time series analysis

I would like to perform an interrupted time series analysis to look at the impact of the pandemic on cancer incidence using individual level data. I plan to use a negative binomial segmented ...
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### transforming a continous respond variable into a discrete one

I am visually estimating fish length underwater to convert it in fish biomass by means of proper length-weight relationships. Obviously, my accuracy is not perfect. When making hypothesis about ...
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### How to construct confidence intervals for difference of means in logs

I have estimated an OLS model and a Negative binomial model of ln housing search (ln S) per unit (for instance, the average number of visitors per house or bidders per house) as a function of ...
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### From overdispersion to underdispersion: comparing linear regression models with DHARMa

I have been investigating the relationship between the occurence of certain weather phenomena and time. To aid me in evaluating the fit of my (simple linear-regression) models, I have been using the ...
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### Can I use the Negative Binomial distribution to calculate the max number of trials where I have less than X fails with some confidence?

Thank you in advance for any help. I am trying to compute the maximum number of times I should expect to attempt a Bernoulli trial to keep my number of fails (with probability of failing $p$) under ...
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### The sum of two Negative Binomial variables doesn't follow a Negative Binomial

I assume that the number of home corners and away corners would follow the Negative Binomial Distribution and I expect that these two variables have the same parameter ...
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### Can a covariate also be a random effect in glmmTMB model with ar1 [closed]

I have data consisting of catches of insects at weekly intervals over 2 years, repeated with the same methods at the same location 3 decades later. My main question is, have numbers (total and for ...
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