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.

Filter by
Sorted by
Tagged with
2
votes
1answer
13 views

How can I interpolate within a negative binomial distribution?

I have information about a negative binomial distribution at the 10%, 50%, and 90% quantiles. I want to be able to interpolate to know what the probability of a certain count is within this ...
0
votes
1answer
17 views

Is there a way to supress p-values in tbl_regression function in R? [closed]

I want to make tables including exponentiated parameter coefficients with CIs, but not with p-values. Right now i am using : ...
1
vote
0answers
30 views

Likelihood loss function for finite support probability distribution in Neural Networks

I have managed to reproduce solution from this article and made it work for my dataset. Instead of making a Neural Network output a scalar (regression), we make it output two parameters of a ...
0
votes
1answer
18 views

Why p-values are inconsistent when applying model on subsetted data versus using interaction terms

I have the following negative binomial GLM, where "group" is either Control or Experimental and "count" shows the number of times patient came to hospital. ...
0
votes
0answers
6 views

Why can negative binomial regression be used to model event rate/count data

It seems negative binomial regression can be used interchangeably with Poisson regression to model event rate? but I don't understand how it works. Poisson distribution is for count data. Poisson ...
2
votes
1answer
56 views

How to account for temporal autocorrelation in a hierarchical generalized additive model (HGAM/GAMM) with a negative binomial distribution?

I am using a harvest data set (count data) that I am trying to infer population abundance from. This data set contains annual harvest estimates from 20 Zones of varying areas, spanning 34 years. While ...
0
votes
0answers
4 views

GLMM appropriate for constant covariates/ baseline score? Or Ancova?

I was wondering whether my data is appropriate to fit a glmm (with r package lme4) So, I measured a questionnaire two times (q1 and q2). Also, I have variables ...
0
votes
0answers
18 views

Intuition for reasoning between Quasi-poisson and Negative Binomial regression

I am aware of the several similar questions existing here (like this, this or this), but my question is slightly different and remains after going through most of those posts. Specifically, my ...
1
vote
1answer
27 views

Applying count models with rate responses

How do you apply count models to data which is count in nature, but a rate in reality? In such cases, r can handle this to a certain extent, depending on the model, but what is the correct way to ...
0
votes
0answers
17 views

quasi-poisson / Neg.Bin / Chi-square for analysing annual count data?

I'm interested in looking at annual trends. The numbers represent the total number of a particular animal species that have been counted in that year. We see a decreasing trend, and I would like to ...
2
votes
2answers
41 views

Excessive amount of zeros - percentage data

I am totally new to using glm-function. I have tried to model my data with lmer-function but the excessive amount of zeros skew the residuals heavily (cubic root transformation helps some tho). The ...
0
votes
0answers
11 views

Poisson Approximation to Negative Binomial

While r tends to infinity, p tends to 1, and (1-p)r tends to lambda, we obtain Poisson distribution from Negative Binomial Distribution. X in Neg Binom(r,p) is the number of failures; x=0,1,2,3,4.... ...
0
votes
0answers
29 views

What is the difference between conditional and unconditional fixed effects?

What is the difference between unconditional and conditional (fixed effects negative binomial) regression models? A similar question was asked for quantile regression here: What is the difference ...
0
votes
0answers
17 views

Analyze count data errors of commissions - is my model fine?

Is my model doing a good job here? I have errors of commission in a SART-task as a dependent variable and stress index and its interaction with a group (2 groups) as an independent variable. The ...
0
votes
0answers
15 views

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? ...
2
votes
0answers
21 views

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 $...
0
votes
0answers
20 views

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 ...
0
votes
0answers
26 views

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 ...
1
vote
2answers
47 views

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 ...
0
votes
1answer
21 views

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 ...
2
votes
2answers
28 views

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 ...
0
votes
0answers
37 views

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 ...
0
votes
0answers
41 views
0
votes
0answers
32 views

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 ...
0
votes
0answers
34 views

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): ...
0
votes
0answers
15 views

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 ...
2
votes
1answer
33 views

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 ...
0
votes
0answers
32 views

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 ...
0
votes
0answers
23 views

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 ...
0
votes
0answers
9 views

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 ...
3
votes
1answer
27 views

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 ...
0
votes
0answers
37 views

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 ...
0
votes
0answers
11 views

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: ...
1
vote
1answer
27 views

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?
0
votes
0answers
24 views

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 ...
1
vote
2answers
80 views

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 ...
0
votes
0answers
17 views

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 ...
0
votes
0answers
12 views

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 ...
0
votes
0answers
11 views

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 ...
1
vote
1answer
26 views

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 ...
2
votes
1answer
49 views

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 ...
3
votes
1answer
58 views

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 $...
0
votes
0answers
15 views

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 ...
0
votes
1answer
27 views

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 ...
1
vote
0answers
101 views

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 ...
2
votes
1answer
92 views

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....
3
votes
1answer
51 views

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: ...
0
votes
0answers
20 views

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. ...
2
votes
1answer
47 views

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 ...
1
vote
0answers
77 views

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 "...

1
2 3 4 5
16