Fit Line to QQ-Plot in Panel
USAGE: 
panel.qqmathline(y, distribution, ...)
y:
sample of data.
distribution:
a quantile function for the reference distribution.
...:
graphical parameters that are passed to panel.abline.
SIDE EFFECTS:
The panel.qqmathline function fits a line to a QQ plot with the specified reference distribution by drawing the line through the quartiles of the data and the quartiles of the reference distribution.
SEE ALSO:
prepanel.qqmathline , qqmath .