Breaks for histogram. If missing defaults to those
generated by hist(x, right = FALSE, plot =FALSE). If
startValues = "LA" then 30 breaks are used by default.
startValues
Code giving the method of determining starting
values for finding the maximum likelihood estimates of the
parameters.
paramStart
If startValues = "US" the user must specify a
vector of starting parameter values in the form
c(mu,log(delta),beta,log(nu)).
Details
startValues can be either "US"(User-supplied) or
"LA" (Linear approximation).
If startValues = "US" then a value for paramStart must be
supplied. The parameters are checked for validity by the function
skewhypCheckPars.
If startValues = "LA" a linear approximation is made to the
log-density in each of the tails, from which the estimates for
nu and beta are found. The remaining two
parameters, delta and mu are found by solving
the moment equations for mean and variance. Since the variance does
not exist for values of nu <= 4, the estimate of
nu will be at least 4.1. Note that if the distribution is
too skewed, there are not enough points in the lighter tail to fit the
required linear model, and the method will stop and return a
warning. User supplied values will have to be used in this case.
Value
skewhypFitStart returns a list with components:
paramStart
A vector of the form c(mu,delta,beta,nu)
giving the generated starting values of the parameters.
breaks
The cell boundaries found by a call to hist.
midpoints
The cell midpoints found by a call to hist.
empDens
The estimated density at the midpoints found by a call
to hist if startValues = "US" or
density if startValues = "LA".
svName
Name of the method used to find the starting values.