# Questions tagged [zero-inflation]

Excessive 0's in a variable compared to a specified reference distribution. Regression approaches include zero-inflated models and hurdle (2-part) models. For count data, zero-inflated and hurdle models based on Poisson or negative binomial distributions are common (ZIP/ZINB and HP/HNB).

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### Residuals in Zero-Inflated Negative Binomial Regression

What do residuals mean in the context of zero-inflated negative binomial regression? I'm learning zero-inflated negative binomial regression. The data is from a state education system and includes ...
633 views

### Dispersion parameter in mass and PSCL package (zero-inflated negative binomial and negative binomial)

I have run Zero inflated negative binomial and negative binomial model with same data set in R. I get log(theta)= -2.47 for Zero inflated negative binomial and log(theta)= -5.149 for negative binomial ...
428 views

### generation of zero-inflated Poisson data in R

I want to generate data from a zero-inflated Poisson distribution in R using the mpath package in the following way: ...
306 views

### How to fit Anomaly Detection model to imbalanced time series data(Zero Inflected time series data)?

I'm doing a predictive modeling for predicting anomalies in the sensors data. For this I'm using the twitter AnomalyDetection package in R. We are getting ton of data from sensors for every day. For ...
183 views

### Zero in proportion data

I am counting the proportion of seeds that have germinated (RV) in petri dishes. 5 petri dishes each had 25 seeds in them. Treatment (EV) was applied. No seeds germinated. When this is put through the ...
613 views

### Fitting custom distributions by MLE

My question relates to fitting custom distributions in R but I feel it has enough of a probability element to remain on CV. I have an interesting set of data which has the following characteristics: ...
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### How can I compare two variables when one has lots of zeros?

Specifically, I want to understand the contributions to insurance premiums and claims. In this case, everyone pays a premium, but only some people make claims. I want to understand whether the ...
481 views

### Deviance in hurdle model

How can I calculate the deviance for the factors and the null and saturated models with Hurdle models? I used the function hurdle() from the package ...
1k views

### GAMM with zero-inflated data

Is it possible to fit a GAMM(Generalized Additive Mixed Model) for zero-inflated data in R? If not, is it possible to fit a GAM(Generalized Additive Model) for zero-inflated data with a negative ...
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### Need for zero-inflated poisson even though model fits data?

Have run a glm with Poisson-distributed errors on count data with 6 treatments and control. The output shows Residual deviance is 96.5 on 91 degrees of freedom, and result of: ...
365 views

### What tests to use for zero-inflated count data that does not fit a poisson distribution? (N=2500) [duplicate]

I have a dataset of roughly 2500 people. One of the variables I have is the number of days people shared different types of content on a social media platform. The most frequent value is 0, with low ...
282 views

### Zeroinfl Package in R [duplicate]

I've fit a dataset using the zeroinfl model with a poisson regression. I'm having trouble understanding why it is that when I use the predict function, all of the values are non-zero. I know that I ...
476 views

### Coding a Zero Inflated Poisson with regression on p and lambda in r

I am trying to fit a zero-inflated Poisson with regression parameters for lambda as well as p. I am following the framework of: "Zero-Inflated Poisson Regression with an Application to Defects in ...
1k views

### Type I and Type II negative binominal distribution in zero inflated negative binominal (ZINB) model

When is it appropriate to use a Type I versus Type II negative binominal distribution in a zero-inflated negative binominal distribution? I've found a Similar question, but without an answer I can ...
644 views

### Does there exist zero-inflated linear regression?

I have a non-count data with huge number of zeros in the target variable. I need to fit a model being a mixture of Dirac delta function and normal distribution parametrized by mean $X\beta$ and ...
177 views

### Exponential-like distribution for positive data

I am trying to predict the number of events happening with the next time window, given the current values of some input variables. I am trying to pick up a good family of distributions to describe ...
106 views

### What “theoretical problems” are associated with Zero-inflated negative binomial models

I just finished a course in regression on count based outcomes. We studied various distributions such as the Poisson and Negative Binomial. Towards the end of the course, we discussed Zero-Inflated ...
43 views

### Regression with review scores containing excess zeroes

Here is an imaginary problem, representing something I am dealing with right now. We have a set of movies with averages scores ranging from 0 to 10, such that the target is a continuous variable. By ...
9k views

### Fitting a model to a variable with many zeros and few but large values in right tail [duplicate]

I would like to fit a model to a dependent variable distributed like the one below (see picture). The distribution is a count of people (with specific characteristics) in various districts. This ...
167 views

### Weird beta inflated distribution qq plot (easy reproducible code included)

First, I do this library(gamlss) simnorm <- rnorm(1000, 0.5,0.1) simzero <- rep(0,1000) x <- sample(c(simnorm,simzero),1000, replace = TRUE) which ...
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### Zero-inflated model does not produce zeroes in fitted values? [duplicate]

I have used GAMLSS to fit a zero-inflated model. However, when I then turn around and FIT that model, it produces absolutely no zeroes at all (even though the data used to fit the model is about 40 % ...
6k views

### Zero inflated distributions, what are they really?

I am struggling to understand zero inflated distributions. What are they? What's the point? If I have data with many zeroes, then I could fit a logistic regression first calculate the probability of ...
578 views

### Zero inflated negative binomial regression dummy variable effects

I am running a zero inflated negative binomial model (zinb) and want to interpret the main and interaction effects. I have the following: People decide whether to purchase a good during a given ...
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### Unusual residual plot of mixed effects model fitted with lme in R (zero-inflated DV?)

I ran a mixed effect model in R by using lme() to analyze the following data (an excerpt is shown in the following): ...
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### How do mixed models deal with a group whose response has zero mean and variance?

I have written a mixed model (following syntax in R package lme4) such as: ...
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### Zero-inflated + thick-tailed + unbalanced panel

I'm pretty new to statistics and need advice on how to analyse zero-inflated, thick-tailed, panel distributions. My sample is a count of enterprise births per city and per year across U.S. cities and ...
201 views

### Interpreting results from distribution fitting

I am trying to determine distribution if this is possible with my data set. After I analyze my data I find that there is possible zero inflated model since there are around 80% of zeros in data set (...
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### Errors in Zero-inflated glm model

I have a count data set with lots of 0 Zero-inflated data set The dataset contains responds(which is the count data) and also three factors:temperature, food type, food concentration. The data like: ...
880 views

### Zero-inflated independent variable for multiple regression

I'm trying to model a continuous response variable with multiple linear regression. One of my independent variables is continuous, highly symmetric but heavily zero-inflated - only 2% of the data ...
329 views

### Zero inflated negative binomial distribution expected frequency

I have data vector and I am trying to do chi square test. This test use frequency from real data and expected frequency. my data ...
303 views

### Negative binomial regression - only for count data?

I've been pouring over statistics blogs over the last couple days to find a satisfactory answer to this, but I can't seem to find one, so I'll pose it to you in hope of a quick fix. Basically, I'm ...
858 views

### Is this zero inflated negative binomial distribution?

I have this vector data and I am trying to find distribution that this data fits. ...
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### Which link function for a cross-lagged panel model with zero-inflated data?

This is my first post here so apologies for the rather basic question, but after days of reading I still can't find a satisfactory answer. I want to run a cross-lagged panel model on three waves of ...
4k views

### Why exactly can't beta regression deal with 0s and 1s in the response variable?

Beta regression (i.e. GLM with beta distribution and usually the logit link function) is often recommended to deal with response aka dependent variable taking values between 0 and 1, such as fractions,...
586 views

### Use loess regression with many zero values

I have measuments of vegetation coverage on Y plotted against surface height (and hence flooding frequency) on X. The vegetation often has two herb layers, which are estimated seperately. If only one ...
823 views

### Zero-inflation with binomial data?

So I have a presence/absence (1/0) dataset and right now I am trying to find out which model to use. My data looks like this: Dependent var: presence/absence (95% zero's) Independent var: month (1:12),...
404 views

### Calculate R2 for a GLMM using glmmADMB

I am trying to calculate an R2 value to explain the variance in my model for a GLMM. My model is run using the glmmADMB package in R since the model is zero-inflated and overdispersed. I have run a ...
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### Implementing a hurdle/Zero-inflated Poisson model in R with right-censored count data

I'm trying to fit a hurdle/zero-inflated (I haven't decided yet) model on microbiological water quality data that is also right-censored: either the water sample is contaminated with bacteria or not, ...
145 views

### Continuous response variable with zeros (Functional Data Analysis)

I am using functional linear model for scalar response. It is that I have i.e. data frame with five columns. Every value in these columns is pressure estimation to certain time ( let's say every 0.04 ...
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### Zero inflated model for censored data

I have a zero-inflated model with censored data Is there a package in R that can combine zero- inflated model with right-censored data? Alternatively, is there a general way to model right-censored ...
342 views

### Fitting distribution for count data

I am interested to fit distribution to the count data presented as histogram below: Is there a way to understand what is the most likely distribution of the data without apriori hypothesizing the ...
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### What is Mu in zero/one beta inflated models? (gamlss (BEINF))

I am estimating a zero/one inflated beta regression model with gamlss (family BEINF). My dependent variable is [0,1] with a lot of 0s, quite some 1s, and some values in between. This means I assume ...
698 views

### linear mixed model with response variable with many zeros

My response variable is accuracy (0 or 1) with 10 trials per subject. I thought about treating the response variable as a percentage and logit-transforming it to deal with its boundedness so that the ...
156 views

### Treating zeros slightly differently for input in a glm / logistic regression

I have data that looks like this: ...
291 views

### Traceplots and gelman.rubin statistics for analysing convergence of mixtures of discrete and continuous distributions

I have a Bayesian hierarchical model which contains a number of distributions which are mixtures of a point-mass at zero and a continuous random variable. The model is fitted using a gibbs sampler. ...
218 views

### How to interpret conflicting results between the binomial and count part of a Zero-Inflated Poisson model?

In my model one of my variables (X2 below) is significant and has a negative sign in both the binomial and count parts of a ZIP model. I was wondering how to ...
3k views

### Exact difference between two-part models (e.g., Cragg) and Tobit type 2 models (e.g., Heckman)

I want to run a regression where the DV is the amount of funding (in USD) obtained by startups. Naturally the DV contains a lot of zero's (~55%) and has a continuous distribution for y>0. In general ...