Questions tagged [negative-binomial]

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

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Truncated NB? Or go with linear?

I am not here to ask about which R package to use, etc. I am here about model selection. The question I am trying to analyze is - What is the association between Indicator 1 and age, sex, and group? ...
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Variance of negative binomial given an offset

Given observations $Y_1, \ldots, Y_n$ from the negative binomial distribution, $NB(\mu, \theta)$, and assume that we model the mean with a GAM: $$\log E(Y_i) = \log \mu_i = \log t_i + f(x_i),$$ where $...
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Find Infection Rate Pattern (Rt), muT and sizeV (parameter in Covid-19 Simulation [closed]

I'm working on an article and I want to do a simulation of Iran's Covid-19 data. The article is "A novel Monte Carlo simulation procedure for modeling COVID-19 spread over time Abstract". I ...
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How To Calculate Infection Rate In Covid 19 Computer Simulation? [closed]

I have an algorithm for simulating the covid 19's Infection in every country. I want to calculate the RT or infection rate based on the population. How should i calculate RT or infection rate pattern ....
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Bayesian r2 for negative binomial

I would like to calculate a R2 value for a Bayesian model with a negative binomial distribution. I have commands to calculate gaussian or binomial, but I was wondering if anyone knew of methods to ...
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Poisson/NB regression with lags on Time Series data

I'm trying to put together a prediction tool for counting time series data. My idea is to go with a lagged Poisson/Negative Binomial regression model. However, I'm uncertain about a many things. Is ...
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Multiple Poisson regression (?) in R

My data consists of 1 dependent variable and 4 independent variables, all the IV's are continuous. Some of my data is presented below to give an idea of how it is structured. The dependent variable is ...
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Dataset with low and non-linearly correlated variables: suggestions on modelling strategies

I have a dataset with low and non-linearly correlated variables and I am interested in assessing the relations between the Independent Variable (IV) and Dependent Variable (DV), however I am not able ...
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Appropriate statistic for describing differences between nested regression models?

I have run a series of nested binary logistic and negative binomial regression models in SPSS examining the impact of an intervention on re-offending outcomes. For example: Model A = Individual ...
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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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Approximate probability of minimum n such that the sum of n Bernoulli random variables is greater or equal to 1000 [duplicate]

Let $X_i$, $1 \le i \le N$ be iid Bernoulli random variables with $P(X_i = 1) = 0,92$. Let $N = min\{n: \sum_{i=1}^{n} X_i \ge 1000\}$. What is the approximate probability of $N$ being greater than ...
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Negative binominal regression with aggregated data in Stata

A question concerning the effect of aggregation level on negative binominal regression estimates. Example with Stata. Say I have the following data (showing first rows of an an example data): ...
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Offset not working well in negative binomial

I have been trying to add an offset to a negative binomial model. My response variable is the number of movements an animal makes. The videos that are used to obtain these measures vary in length, so ...
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incidence rate ratio after negative binomial results in R

I am trying to calculate the incidence rate ratio of my negative binomial model. After running my negative binomial regression model, I use exp(Mymodel) in order to get the incidence rate ratio but R ...
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Error when adding Autocorrelation in GAMM

I am fitting a Generalized Additive Mixed Models (GAMM) model to establish possible relationship between explanatory variables (Temperature,Humidity,Rainfall and Wind speed) and HFMD disease data. I ...
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How to find the parameters for negative binomial CDF from my data?

I am having difficulty trying to determine how I should find the parameters for two functions which are inter-dependent: pnbinom and ...
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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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How to statistically test if the dispersion parameter in a negative binomial distribution is different?

I have a negative binomial distribution for two species. I have been able to fit (dummy) data to estimate mean (mu) and dispersion parameter (size). However, I want to statistically test if the two ...
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Generalized estimating equations (GEEs) for zero-inflated models

I have a dataset of matched pairs and was initially planning on running a Poisson mixed-effects model. However, GEEs seem more appropriate for my research question since they are "population ...
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Can I interpret significant IVs from a negative binomial regression if the goodness-of-fit chi-squared test is significant (ie poor fit?)

I have a negative binomial regression that has the following model statistics: ...
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How to calculate sample population with species of known probability

I have a sample of n=200,000 from 300 species. 8 species cover 80% of the samples. How can I calculate the right sample size such that each species has at least 1000 samples?
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Confidence intervals of risk ratios from Poisson/negative binomial regression

Maybe a simple question: In Poisson regression or negative binomial regression I can get the relative risk (RR) of a predictor by exponentiating the estimated coefficient $\beta$. To get a confidence ...
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Interpret negative binomial coefficients and p-value

I fit a negative binomial model for my dataset because of over-dispersion in the poisson model. DOWFACAT and SSNVOLCLS are categorical. All other variables are ...
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Difference between the coefficients from a Poisson/Negative Binomial regression, and the partial effects

My understanding is that a Poisson/Negative Binomial regression takes the form of a log-level model, and therefore, the resulting beta coefficient can be interpreted as the beta*100% change in y due ...
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Method of Data-Analysis

For my research I'm examining whether applying a certain promotional intervention improves the amount of misshapen products bought. The study contains of two parts. In part 1 Scanner data from ...
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MLE for negative binom

for r= successes and x= failures, if the MSE of its MLE approaches 0 as r approaches infinity can I say that it is consistent and unbiased asymptotically for r or does the term consistent and unbiased ...
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Best GLM to model a random variable that represents a count over a non-fixed interval of time

The random variable on which I am seeking to fit a GLM is the number of times a patient has a blood glucose level measurement above a specified threshold before they are escalated onto a stronger ...
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MLE and Methods of Moments of Negative Binomial in R

Question Let's say we define the Negative Binomial as follows: $$f(x) = {x+r-1 \choose x} p^x (1-p)^r$$ With mean and variance: $$E(x) = \frac{rp}{1-p} \quad \quad V(x) = \frac{rp}{(1-p)^2}$$ We are ...
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How to properly write negative binomial regression?

I am modeling the number of likes in a given hour, where $y_t$ gives the number of new likes on an item in the hour $t$, and seeing how the slope changes after a certain break-point. I assume that $...
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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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Trials not starting from 1 - Negative binomial

Trying to tabulate the pmf and cdf of a negative binomial distribution. I have a probability of 0.75, and an success of 2, where ...
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Partial Residual plots for Zero-Inflated Negative Binomial Models?

I am looking for guidance on how to create partial residual plots for zero-inflated negative binomial (ZINB) models in R. I am quite new to R and have done a lot of research on my questions but have ...
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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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report negative biomial models (glmer.nb) in APA-Format: log-link?

So far I fitted my generalised mixed model with a negative binomial distribution (glmer.nb) and I like to report the results now. The output looks like this: ...
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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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Comparison of different statistical tests on different amount of biological replicates

I am testing differentially expressed genes using different statistical tests on different amount of biological replicates (Wilcoxon test, t-test and negative binomial test). Figure below is what I ...
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How to create average model of multiple negative binomial models?

I have 40 datasets, i manage to fit them to negative binomial model with different model parameters (size and mu). I am trying (if this is possible) to get resultant model that will replace "...
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How to fit simple count data to model in order to generate new dataset

I have simple count data set in a form of data vector PC6. I am trying to identify distribution in order to create pseudo generator for my simulation. Freq table of my data is ...
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GLM with binomial function in R with Tukey HSD comparison

I need help to calculate the binomial function using glm model in R for the below data can anyone help me to find how to arrange data commentary and analysis codes.
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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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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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How to determine a probabiltiy vector for a chi sqare goodnes of fit test?

I have numerical vectors of data that represent number of emails per day send by user (one variable). I want to run a simulation where I will be able to simulate mail creation process for about 30 ...
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Zero-inflated negative binomial model standard error too high?

I've been trying to analyze count data for ant foragers visiting on extrafloral nectaries with R. My data is both overdispersed and zero-inflated, so I used a zero-inflated negative binomial model to ...
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Multiply beta coefficients from two different models

I have a count outcome with a heavy right skew that is modeled with a negative binomial. I have a continuous mediator that is modeled with OLS. We're attempting a method of causal mediation analyses ...
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How to compare a negative binomial, uniform, and random distribution?

I have these frequency distributions in various treatment combinations (1/6; 1000/10000; two players (red/blue)). In hypothesize that the player counts can distribute in neg binomial, random, or ...
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Elasticity of negative binomial regression?

How to find the elasticity of a negative binomial regression when the independent variables are numeric, categorical, or dummy variables? Edit: For example, ...
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Why do epidemiologists fit the number of transmission cases with negative binomial distribution?

In the recent paper on coronavirus spread in Hong Kong, the number of individuals infected by one person (relative to all transmission cases) is fit by a negative binomial distribution. Why is that? ...
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Merging several models in to “average” one

I made several models (30 models) that are created from datasets that belongs to separate sources (data from different users for same activity). All data models follow negative binomial distributions ...
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Reparameterizing PDF to get components of exponential family

For the following problem, I am trying to identify the components of the exponential family in the form: $\exp(y\theta - b(\theta))/a(\phi) + c(y; \phi)$ Namely, I need to identify the $\theta, b(\...

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