gen.freq.curves {lmomco} | R Documentation |
This function generates random samples of specified size from a specified parent distribution. Subsequently, the type of parent distribution is fit to the L-moments of the generated sample. The fitted distribution is then plotted with the built-in function lines
. It is the user's responsibility to have an active plot
already drawn; unless the callplot
option is TRUE
. This function is useful to demonstration of sample size on the uncertainty of a fitted distribution—a motivation for this function is for class room exercise.
gen.freq.curves(n, para, F=NULL, nsim=10, callplot=TRUE, aslog=FALSE, asprob=FALSE, showsample=FALSE, showparent=FALSE, ...)
n |
Sample size to draw from parent as specified by para . |
para |
The parameters from lmom2par or similar. |
F |
The nonexceedance probabilities for horizontal axis—defaults to nonexceeds when the argument is NULL . |
nsim |
The number of simulations to perform (frequency curves to draw)—the default is 10. |
callplot |
Calls plot to acquire a graphics device—default is TRUE , but the called plot is left empty. |
aslog |
Compute log10 of quantiles—note that NaNs produced in: log(x, base)will be produced for less than zero values. Otherwise this is a harmless message. |
asprob |
The qnorm function is used to convert nonexceedance probabilities, which are produced by nonexceeds , to standard normal deviates. The normal distribution will plot as straight line when this argument is TRUE and aslog=FALSE . |
showsample |
Each simulated sample is drawn through plotting positions (pp ). |
showparent |
The curve for the parent distribution is plotted on exit from the function if TRUE . Further plotting options can not be controlled—unlike the situation with the drawing of the simulated frequency curves. |
... |
Additional parameters are passed to the lines call within the function—except for the drawing of the parent distribution (see argument showparent . |
No value is returned. This function is used for its graphical side effects.
W.H. Asquith
lmom2par
, nonexceeds
, rlmomco
, lmoms
para <- vec2par(c(140,4),type='gam') # build a gamma parent F <- nonexceeds() # vector of nonexceedance probabilities Q <- quagam(F,para) # the quantiles of parent distribution # simulated are grey, parent is black gen.freq.curves(10,para,nsim=15,asprob=TRUE,showparent=TRUE,col=8)