Statistical Analysis Stack Exchange
Statistical Analysis Stack Exchange

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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What is the difference between zero-inflated and hurdle models?

I wonder if there is a clear-cut difference between the so-called zero-inflated distributions (models) and so-called hurdle-at-zero distributions (models)? The terms occur quite often in the literature and I suspect they are not the same, but would…
skulker
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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 zeroes, and then I could remove all the zeroes,…
Calro
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Two-part model: is it necessary to use the same regressors in both parts?

I am implementing a two-part model where the first part is a probit/logit and the second part an OLS. Is it necessary to use the same regressors for both parts or can I use different variables? In particular, I only have one regressor, say $x$, to…
Nicolas L
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How to estimate the probability of structural zeros for zero inflated distributions?

I am in need of using the cumulative density functions from either the zero inflated Poisson or zero inflated negative binomial. The methods ask that you supply: pstr0: Probability of a structural zero (i.e., ignoring the Poisson distribution),…
John Stud
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Zero Inflated Poisson model, estimation of vectors beta and gamma

I'm working on zero inflated poisson models but I have a doubt on the estimation of the coefficients. Suppose that I have a small sample of data (just for an example, 10 policies with just 4 covariates (maybe sex, age, family composition and…
Castels
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Statistical Procedures in Heavy Zero Density Data

How do procedures such as Principal Component Analysis, Logistic Regression, Cross Validation perform under Zero under Zero Heavy Data? Are they sub-optimal or simply inadequate?
stats_noob
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not concave iterations on a zinb model

my name is vincenzo and i have that type of problem with zinb that you intorduce in this discussion (ZIP converges but ZINB does not. Should I drop this model?): the iterations continues to be not concave. If I take out one variable from my model,…
Vincenzo
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Zero inflated Ordered Probit/Logit Model

I have data with some ordinal component of Injury severity, measured as property damage, Fatal or Killed. Is there an R package for the Zero-inflated ordered Probit / Logit models?
Code newbie
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Model for Time-To-Event Where It Is Known That The Event Did Not Occur If It Is Unobsered

I have a dataset with time-to-event data (so this is a continuous outcome). The data, however, is such that I do know that when the event did not occur - then it did not happen. What could be an appropriate model approach for this scenario? I was…
clog14
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Zeroinflated and degree of freedom

I am using zeroinfl test with my data, and was wondering if it is enough to mention the z value in a paper. Otherwise, I used the lrtest to calculate the X² and p values as…
Ismail
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What coefficients to include in logit component of zero-inflated and hurdle models?

I'm new to statistics so hoping for a ELI5 explanation! I need to use a hurdle (or zero-inflated) model to try and replicate someone elses methodology on a newer dataset for my undergraduate dissertation. I ran the model using the pscl package in R…
user242884
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Testing for zero inflation and overdispersion in count time series data?

How can I test whether my data is really zero inflated? Can I use the same methods as for count data? Thank you.
Krishnee
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