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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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 ...
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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 :
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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 ...
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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.
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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....
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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 ...
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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 ...
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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?
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0answers
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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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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 ...
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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 ...
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2answers
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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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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 ...
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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 ...
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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 ...
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41 views
Justification of the log transformation of independent variables [duplicate]
I have used the following negtaive binomial model:
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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 ...
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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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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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:
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1answer
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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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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 ...
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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 ...
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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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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 ...
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1answer
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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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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 $...
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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
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0
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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 ...
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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
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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
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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:
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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. ...
2
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1answer
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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 "...
