Hello,

I never placed a question here, so first time questioner. I have performed a Zero-One-Inflated-Beta regression with logit link in R. The conditional effects can be extracted which is useful for plotting given it returns the intervals. Yet, when I calculate backwards from the values returned to the expected value (ZOIB and B [without ZOI]) and compare this with the expected values the Brms function conditional_effects returns, the trend lines do not match. Also, these manual derived values match much better with the data, Iāve been scratching my head for a few days now. And, if I am correct then the expected value should be:

E(y|x)=exp(Ī²+Ī²1x1+Z1+C1)/(1+exp(Ī²0+Ī²1x1+Z1+C1))

The question is why donāt the expected values match, where do I go awry?

Thank you in advance

P.S. Duplicated question from https://www.researchgate.net/post/Why_does_the_trend_derived_from_ZOIB-model_Brms_not_overlay_manual_calculated_trend

P.P.S. Visualizing conditional effects plot for e.g. zi parameter - #2 by paul.buerkner

brack_frac_mod.RData (2.7 MB)

brack_frac.RData (9.7 KB)