I have some observations $y$ which have only few negative values $y_i\in (-\infty,0)$ and mostly non-negativ values, i.e. $y_i\in [0,\infty)$. I would like to estimate a censored logistic distribution depending on some variables x1, x2
for y
with GAMLSS. Therefore I assume that the y
is left-censored at zero (as nearly all values are non-negativ). However, I am not sure, if I specified the formula
part with the survival object for this model correctly in GAMLSS. I used the following R-code
# generates left censored logistic distribution called "LOlc"
gen.cens(family = "LO", type = "left")
# estimate model
model <- gamlss(formula = Surv(y, y >= 0, type = "left") ~ x1 + x2,
sigma.formula = ~ x1 + x2,
nu.formula = ~ 1,
tau.formula = ~ 1,
family = "LOlc", #
data = na.omit(data))
Could you tell me, if I specified Surv(y, y >= 0, type = "left")
in the formula
argument correctly and if I generated the correct distribution for my assumption with gen.cens
for this situation?
Thank you!