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Question about zero-inflated Poisson glmer

Thierry Onkelinx 
Dear Philipp,

Do you have just lots of zero's, or more zero's than the Poisson
distribution can explain? Those are two different things. The example below
generates data from a Poisson distribution and has 99% zero's but no
zero-inflation. The second example has only 1% zero's but is clearly
zero-inflated.

set.seed(1)
n <- 1e8
sim <- rpois(n, lambda = 0.01)
mean(sim == 0)
hist(sim)

sim.infl <- rbinom(n, size = 1, prob = 0.99) * rpois(n, lambda = 1000)
mean(sim.infl == 0)
hist(sim.infl)

So before looking for zero-inflated models, try to model the zero's.

Best regards,


ir. Thierry Onkelinx
Instituut voor natuur- en bosonderzoek / Research Institute for Nature and
Forest
team Biometrie & Kwaliteitszorg / team Biometrics & Quality Assurance
Kliniekstraat 25
1070 Anderlecht
Belgium

To call in the statistician after the experiment is done may be no more
than asking him to perform a post-mortem examination: he may be able to say
what the experiment died of. ~ Sir Ronald Aylmer Fisher
The plural of anecdote is not data. ~ Roger Brinner
The combination of some data and an aching desire for an answer does not
ensure that a reasonable answer can be extracted from a given body of data.
~ John Tukey

2016-06-23 10:07 GMT+02:00 Philipp Singer <killver at gmail.com>:

  
  


  


  


  
  

    

  

    
      
    
    
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        Philipp Singer
        
        Question about zero-inflated Poisson glmer
      
      Jun 23
    
    
      
            
        Thierry Onkelinx
        
        Question about zero-inflated Poisson glmer
      
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        Philipp Singer
        
        Question about zero-inflated Poisson glmer
      
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        Question about zero-inflated Poisson glmer
      
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        Philipp Singer
        
        Question about zero-inflated Poisson glmer
      
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        Question about zero-inflated Poisson glmer
      
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        Question about zero-inflated Poisson glmer
      
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        Question about zero-inflated Poisson glmer
      
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        Question about zero-inflated Poisson glmer
      
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        Question about zero-inflated Poisson glmer
      
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        Question about zero-inflated Poisson glmer
      
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        Thierry Onkelinx
        
        Question about zero-inflated Poisson glmer
      
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        Philipp Singer
        
        Question about zero-inflated Poisson glmer
      
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        Philipp Singer
        
        Question about zero-inflated Poisson glmer
      
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        Thierry Onkelinx
        
        Question about zero-inflated Poisson glmer
      
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        Philipp Singer
        
        Question about zero-inflated Poisson glmer
      
      Jun 27
    
    
      
            
        Thierry Onkelinx
        
        Question about zero-inflated Poisson glmer
      
      Jun 27
    
    
      
            
        Philipp Singer
        
        Question about zero-inflated Poisson glmer
      
      Jun 27
    
    
      
            
        Thierry Onkelinx
        
        Question about zero-inflated Poisson glmer
      
      Jun 27
    
    
      
            
        Philipp Singer
        
        Question about zero-inflated Poisson glmer
      
      Jun 28
    
    
      
            
        Thierry Onkelinx
        
        Question about zero-inflated Poisson glmer
      
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        Philipp Singer
        
        Question about zero-inflated Poisson glmer
      
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        Question about zero-inflated Poisson glmer
      
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