maxwell {VGAM} | R Documentation |
Estimating the parameter of the Maxwell distribution by maximum likelihood estimation.
maxwell(link = "loge", earg = list())
link |
Parameter link function applied to the parameter a.
See |
earg |
List. Extra argument for the link.
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
.
A related distribution is the Rayleigh distribution. Fisher-scoring and Newton-Raphson are the same here.
T. W. Yee
von Seggern, D. H. (1993) CRC Standard Curves and Surfaces, Boca Raton, FL.: CRC Press.
mdata = data.frame(y = rmaxwell(1000, a = exp(2))) fit = vglm(y ~ 1, maxwell, mdata, trace = TRUE, crit = "c") coef(fit, matrix = TRUE) Coef(fit)