ssym: extra.parameter – R documentation

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extra.parameter

Tool that supports the estimation of the extra parameter.

Description

extra.parameter is used to plot a graph of the behaviour of the overall goodness-of-fit statistic and -2\textsf{L}(\hat{θ}) versus the extra parameter ζ in the interval/region defined by the arguments lower and upper. These graphs may be used to choosing the extra parameter value.

Usage

extra.parameter(object, lower, upper, grid)

Arguments

`object`	an object of the class `ssym`. This object is returned by the call to `ssym.l()`, `ssym.nl()` or `ssym.l2()`
`lower`	lower limit(s) of the interest interval/region for the extra parameter.
`upper`	upper limit(s) of the interest interval/region for the extra parameter.
`grid`	Number of values of the extra parameter where the overall goodness-of-fit statistic and -2\textsf{L}(\hat{θ}) are evaluated.

Author(s)

Luis Hernando Vanegas <hvanegasp@gmail.com> and Gilberto A. Paula

References

Vanegas, L.H. and Paula, G.A. (2015b) Log-symmetric distributions: statistical properties and parameter estimation. Brazilian Journal of Probability and Statistics (to appear)

Examples

###################################################################################
############### Textures of snacks Data - a log-Student-t model  #################
###################################################################################
#data("Snacks", package="ssym")
#fit <- extra.parameter(log(texture) ~ type + ncs(week) | type, data=Snacks,
#        family='Student', xi=10)
#summary(fit)
#
############################ Extra parameter ###########################
#extra.parameter(fit,5,50)

###################################################################################
################## Biaxial Fatigue Data - a Birnbaum-Saunders model   #############
###################################################################################
#data("Biaxial", package="ssym")
#fit <- ssym.nl(log(Life) ~ b1*Work^b2, start=c(b1=16, b2=-0.25),
#                data=Biaxial, family='Sinh-normal', xi=1.54)
#summary(fit)
#
########################### Extra parameter ###########################
#extra.parameter(fit,1.3,1.8)

ssym

Fitting Semi-Parametric log-Symmetric Regression Models

v1.5.7

GPL-2 | GPL-3

Authors