5
votes
Accepted
Difference between ZIP and ZIP2
There's more details in the freely available older version of the gamlss book (section 18.2.11-12). The regular Poisson model is parametrized through a mean $\mu$, ...
- 1,956
5
votes
Accepted
How to compare centiles from different models?
Some of the deviations you point to can be due to random variation alone. There are simple ways to test them.
When there are independent observations of a variable whose conditional distributions ...
- 316k
3
votes
How to interpret the p-value associated with the intercept?
I want to establish which interactions of levels of factors are significantly different from the intercept.
You will get into trouble if you only depend on the coefficients and p values displayed ...
- 86.7k
2
votes
Accepted
Interpreting predict() with gamlss() and beta-binomial family=BB
I emailed the primary creator of the gamlss package, Professor Mikis Stasinopoulos, and he was very kind to provide an extensive explanation and correction to my ...
- 2,311
1
vote
GAMLSS: What exactly is the predicted or fitted sigma? why can't I use it to calculate z-score?
In GAMLSS sigma is generally a scale parameter,
but not usually the standard deviation.
If you want the z-score for any distribution,
then it is given by:
first find the probability p of being below ...
- 318
1
vote
Accepted
Standard errors in GAMLSS vs LMER
The standard errors of the gamlss are conditioned on the values of the random component. The lmer standard errors integrate out ...
- 803
1
vote
Accepted
Find the more appropriate fit by using term.plot in GAMLSS
Selecting the best model can be
(i) by choosing the fitted model with lowest generalized Akaike information criterion GAIC(k) for a user chosen penalty k for each effective degree of freedom in the ...
- 51
1
vote
Accepted
qBCCGo function in GAMLSS package (quantile function)
qBCCGo is exact, so use that.
[Note the formula for LLN is approximate and
log(1-1.645 * nu * sigma) will be NA, if 1 < 1.645 * nu * sigma.]
Yes,
for calculating the ULN we need to use
qBCCGo(0.05, ...
- 51
1
vote
qBCCGo function in GAMLSS package (quantile function)
mu=0.8
nu=1.1
sigma=0.4
qBCCGo(0.05, mu = mu, sigma = sigma, nu = nu, lower.tail = TRUE, log.p = FALSE)
gives an exact result.
However
exp(log(mu)+log(1-1.645nusigma)/nu)
is an approximation.
The ...
- 318
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