Maxwell Regression Family Function
Estimating the parameter of the Maxwell distribution by maximum likelihood estimation.
maxwell(link = "loglink", zero = NULL, parallel = FALSE,
type.fitted = c("mean", "percentiles", "Qlink"),
percentiles = 50)link |
Parameter link function applied to a,
which is called the parameter |
zero, parallel |
|
type.fitted, percentiles |
See |
The Maxwell distribution, which is used in the area of thermodynamics, has a probability density function that can be written
f(y;a) = sqrt(2/pi) * a^(3/2) * y^2 * exp(-0.5*a*y^2)
for y>0 and a>0. The mean of Y is sqrt(8 / (a * pi)) (returned as the fitted values), and its variance is (3*pi - 8)/(pi*a).
An object of class "vglmff" (see vglmff-class).
The object is used by modelling functions such as vglm,
rrvglm
and vgam.
Fisher-scoring and Newton-Raphson are the same here.
A related distribution is the Rayleigh distribution.
This VGAM family function handles multiple responses.
This VGAM family function can be mimicked by
poisson.points(ostatistic = 1.5, dimension = 2).
T. W. Yee
von Seggern, D. H. (1993). CRC Standard Curves and Surfaces, Boca Raton, FL, USA: CRC Press.
mdata <- data.frame(y = rmaxwell(1000, rate = exp(2))) fit <- vglm(y ~ 1, maxwell, data = mdata, trace = TRUE, crit = "coef") coef(fit, matrix = TRUE) Coef(fit)
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