continuous {smovie} | R Documentation |
Univariate Continuous Distributions: p.d.f and c.d.f.
Description
A movie to illustrate how the probability density function (p.d.f.) and
cumulative distribution function (c.d.f.) of a continuous random variable
depend on the values of its parameters.
Usage
continuous(
distn,
var_range = NULL,
params = list(),
param_step = list(),
param_range = list(),
p_vec = NULL,
smallest = 0.01,
plot_par = list(),
panel_plot = TRUE,
hscale = NA,
vscale = hscale,
...
)
Arguments
distn |
Either a character string or a function to choose the
continuous random variable.
Strings "beta" , "cauchy" , "chisq"
"chi-squared" , "exponential" , "f" , "gamma" ,
"gev" , "gp" , "lognormal" , "log-normal" ,
"normal" , "t" , "uniform" and "weibull" are
recognised, case being ignored. The relevant distributional functions
dxxx and pxxx in the stats-package
are used. The abbreviations xxx are also recognised.
The "gev" and "gp" cases use the
gev and gp
distributional functions in the revdbayes
package.
If distn = "gamma" then the (shape, rate)
parameterisation is used, unless a value for scale is provided
via the argument params when the (shape, scale)
parameterisation is used.
Valid functions are set up like a standard distributional function
dxxx , with first argument x , last argument log
and with arguments to set the parameters of the distribution in between.
See the
CRAN task view on distributions.
If distn is not supplied then distn = "normal"
is used.
|
var_range |
A numeric vector of length 2. Can be used to set a fixed
range of values over which to plot the p.d.f. and c.d.f., in order better
to see the effects of changing the parameter values.
If var_range is set then it overrides p_vec (see below).
|
params |
A named list of initial parameter values with which to start
the movie. If distn is a string and a particular parameter value
is not supplied then the following values are used.
"beta" : shape1 = 2, shape2 = 2, ncp = 0 ;
"cauchy" : location = 0, scale = 1 ;
"chi-squared" : df = 4, ncp = 0 ;
"exponential" : rate = 1 ;
"f" : df1 = 4, df2 = 8, ncp =0 ;
"gamma" : shape = 2, rate = 1 ;
"gev" : loc = 0, scale = 1, shape = 0.1 ;
"gp" : loc = 0, scale = 1, shape = 0.1 ;
"lognormal" : meanlog = 0, sdlog = 1 ;
"normal" : mean = 0, sd = 1 ;
"t" : df = 4, ncp = 0 ;
"uniform" : min = 0, max = 1 ;
"weibull" : shape = 2, scale = 1 .
If distn is a function then params must set any required
parameters.
If parameter value is outside the corresponding range specified by
param_range then it is set to the closest limit of the range.
|
param_step |
A named list of the amounts by which the respective
parameters in params are increased/decreased after one click of
the +/- button. If distn is a function then the default is 0.1
for all parameters. If distn is a string then a sensible
distribution-specific default is set internally.
|
param_range |
A named list of the ranges over which the respective
parameters in params are allowed to vary. Each element of the list
should be a vector of length 2: the first element gives the lower limit
of the range, the second element the upper limit.
Use NA to impose no limit.
If distn is a function then all parameters are unconstrained.
|
p_vec |
A numeric vector of length 2. The p.d.f. and c.d.f. are
plotted between the 100p_vec[1] % and 100p_vec[2] %
quantiles of the distribution. If p_vec is not supplied then
a sensible distribution-specific default is used. If distn is
a function then the default is p_vec = c(0.001, 0.999) .
|
smallest |
A positive numeric scalar. The smallest value to be
used for any strictly positive parameters when distn is a string.
|
plot_par |
A named list of graphical parameters
(see par ) to be passed to
plot . This may be used to alter the
appearance of the plots of the p.m.f. and c.d.f.
|
panel_plot |
A logical parameter that determines whether the plot
is placed inside the panel (TRUE ) or in the standard graphics
window (FALSE ). If the plot is to be placed inside the panel
then the tkrplot library is required.
|
hscale , vscale |
Numeric scalars. Scaling parameters for the size
of the plot when panel_plot = TRUE . The default values are 1.4 on
Unix platforms and 2 on Windows platforms.
|
... |
Additional arguments to be passed to
rp.doublebutton , not including panel ,
variable , title , step , action , initval ,
range .
|
Details
The movie starts with a plot of the p.d.f. of the distribution
for the initial values of the parameters. Buttons
increase (+) or decrease (-) each parameter. There are radio buttons
to switch the plot from the p.d.f. to the c.d.f. and back.
Value
Nothing is returned, only the animation is produced.
See Also
movies
: a user-friendly menu panel.
smovie
: general information about smovie.
Examples
# Normal example
continuous()
# Fix the range of values over which to plot
continuous(var_range = c(-10, 10))
# The same example, but using a user-supplied function and setting manually
# the initial parameters, parameter step size and range
continuous(distn = dnorm, params = list(mean = 0, sd = 1),
param_step = list(mean = 1, sd = 1),
param_range = list(sd = c(0, NA)))
# Gamma distribution. Show the use of var_range
continuous(distn = "gamma", var_range = c(0, 15))
[Package
smovie version 1.1.6
Index]