QQplot {QRMlib} | R Documentation |
constructs a quantile-quantile plot against a given reference distribution (only normal, exponential, and student-t are currently supported)
QQplot(data, position=0.5, reference="normal", ...)
data |
vector of data |
position |
determines the plotting positions (see ppoints in R-help) |
reference |
name of reference distribution (only normal, exp, student-t currently allowed) |
... |
Any further parameters required by quantile function of reference distribution. For example, if reference="exp", you may want to pass 'rate'. If using the normal distribution, you may want to pass mu and sigma. If using the student-t, you may wish to pass the df parameter. |
Special forms like ParetoQQ plots can also be created via this function. E.g., to create a ParetoQQ plot, merely pass log(data) in place of data as the first parameter and use reference="exp" as the reference distribution. The ParetoQQ plot should provide a linear graph when a log transform of the data is plotted against the exponential distribution. See Beirlant et al, "Statistics of Extremes", Chapter 1.2.1 for descriptions of various QQ plots.
NULL returned
QQ-plot is created on graphical device
QQplot(rnorm(1000),reference="normal"); QQplot(rexp(1000),reference="exp", rate=0.3);