# Tagged Questions

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

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### Converting logarithmically transformed negative binomial coefficients to effect size at mean

I have logarithmically transformed coeficients, from a negative binomial regression, and am looking to calculate from these the unit change in y from a one-unit change in x. It is my understanding ...
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### Expected number of times to roll a die until each side has appeared 3 times

What is the expected number of times you must roll a die until each side has appeared 3 times? This question was asked in primary school in New Zealand and it was solved using simulations. What is ...
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### Obtaining AICc weights after glm.nb

I am performing negative binomial regression using glm.nb() function from MASS package and calculating AICc using package "AICcmodavg". I need also to obtain the (AICc) weights using aictab() function ...
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### negative binomial modelling for child pedestrian accidents

I am currently try to model child pedestrian casualties for each ward in England and to create a model that will predict how many casualties per area based on social and economic qualities of the area ...
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### Negative significance between zeros in GEE-Binary logistic model

In my experiment I record individuals response (yes or no,coded as 1 or 0) to 4 different treatments, in each trial all treatment are tested and repeated 10 times each but in random order. Thus I have ...
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### Comparing results from reference coding and orthogonal coding in a linear model?

The problem: I'm trying to fit a zero-inflated negative binomial model to count data (catches of larval fish). I have three factors, and an offset variable, which is the volume of water filtered by ...
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### Help with zero-inflated generalized linear mixed models with random factor in R

My study has a complicated design and I am not sure if I am modeling my zero-inflated data correctly. I have seed abundances and seedling abundances for 11 species. I have one main "treatment" with ...
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### Plotting Negative Binomial curves in GGplot

I am trying to plot this data with a negative binomial curve and I keep coming up with this warning label. Now, I know what the theta is, but I can not figure out where in the code to specify it. ...
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### zero-inflated negative binomial in Stata

I am trying to run a zero-inflated negative binomial analysis in Stata (zinb). My question/problem is this: the model's convergence seems dependent on which and how ...
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### What component of the result should I look at when doing a LLM model fit?

I am running mixed effects models with poisson and negative binomial fits. To asses which of the models are better, what components of the models should I look at? Some popular methods I follow: a) ...
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### Two more questions about Count Data

I almost became an opponent of the transformation of count data. (quite famous reference). But I still did not find answers to some important questions about non-transformed count data (I consider ...
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### Negative Binomial to Normal

I want to use normalisation technique that has assumption of residuals' normality (GLMs), but my data is $\sim$Negative Binomial. Can I map values from NB distributed distribution to Normal ...
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### Negative Binomial Problem (parameter estimation)

I have quite a tricky problem. Assume we have vector of random variables: $v = \{\xi_1, \ldots, \xi_n\}$. Each random variable is $NB$ distributed. Asuume we have several vectors $v$, and we have ...
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### Zero Inflated Versus Negative Binomial Models Conundrum

I have a count variable that represents the number of new band foundings in a country-year. However, there is zero inflation as there are no foundings for most country-year. There is also ...
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### Dependent variable is count data, which method to use?

Which method should I use to analyse the relationship between count variable (absent days) and other 4 variables? Should I standardise Size variable? Please recommend some further literature/ ...
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### Frequency Data, Model Choice (Poisson with Offset, Fractional Regression)

I have text data and am interested in estimating the effect of some covariate on word frequency. All the frequencies are very small. The unit of observation is a single document. I'm trying to think ...
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### Computing a growth rate starting from a negative-binomial-regression coefficient

I need to estimate the growth rate of a factor in time. The available information consists of a coefficient from a negative binomial regression, where this factor is the dependent variable and time is ...
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### Counts vs. percentage of predictor variables in the presence of an offset

The case: I am using negative binomial models to predict the number of deaths per household for four African countries. I am using an offset (log number of household members) to obtain estimates of ...