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I created the following GAMM function using the R package gamlss:

model<-gamlss(Overlap~ Diff.Long + Diff.Fzp + DiffSeason +
              random(Xnumber),family=BEZI(mu.link = "logit", sigma.link = "log", 
              nu.link = "logit"),data=data,trace=F)

The output of this model is:

******************************************************************
Family:  c("BEZI", "Zero Inflated Beta") 

Call:  gamlss(formula = Overlap ~ Diff.Long + Diff.Fzp + DiffSeason +  
    random(Xnumber), family = BEZI(mu.link = "logit",  
    sigma.link = "log", nu.link = "logit"), data = data,      trace = F) 

Fitting method: RS() 

------------------------------------------------------------------
Mu link function:  logit
Mu Coefficients:
                 Estimate Std. Error t value Pr(>|t|)   
(Intercept)     -0.188647   0.208359  -0.905  0.36715   
Diff.Long       -0.002072   0.000736  -2.814  0.00575 **
Diff.Fzp        -0.030909   0.013749  -2.248  0.02648 * 
DiffSeasonEW-LW -0.617976   0.211260  -2.925  0.00415 **
DiffSeasonLW-LW -0.356989   0.270548  -1.320  0.18963   
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1

------------------------------------------------------------------
Sigma link function:  log
Sigma Coefficients:
            Estimate Std. Error t value Pr(>|t|)    
(Intercept)    1.865      0.126    14.8   <2e-16 ***
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1

------------------------------------------------------------------
Nu link function:  logit 
Nu Coefficients:
            Estimate Std. Error t value Pr(>|t|)    
(Intercept)  -2.3470     0.3156  -7.437 2.02e-11 ***
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1

------------------------------------------------------------------
NOTE: Additive smoothing terms exist in the formulas: 
 i) Std. Error for smoothers are for the linear effect only. 
ii) Std. Error for the linear terms maybe are not accurate. 
------------------------------------------------------------------
No. of observations in the fit:  126 
Degrees of Freedom for the fit:  11.15247
      Residual Deg. of Freedom:  114.8475 
                      at cycle:  5 
 
Global Deviance:     -43.54531 
            AIC:     -21.24037 
            SBC:     10.39118 
******************************************************************

I'm not the most familiar yet with additive models, and am trying to find the significance of my random effect ("Xnumber"). I know that the package mgcv has a way but the package gamlss is the only one to have the distribution I need (zero-inflated beta).

If anyone knows any functions I can use, that would be great? Or is it in the summary, but I just don't know where to look?

Cam
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  • could we have a [mcve] please? FWIW `glmmTMB` can also fit zero-inflated beta responses. Testing significance of random effects is a little tricky: https://bbolker.github.io/mixedmodels-misc/glmmFAQ.html#testing-significance-of-random-effects – Ben Bolker Nov 25 '22 at 00:54

0 Answers0