Quantile-quantile plots are used to compare a "theoretical" or
empirical distribution to a reference distribution. They can also compare the quantiles of two
reference distributions.

`qqplot(x, y, npoints = 3000, idline = TRUE, plot = TRUE, ...)`

## Arguments

- x
`distr6`

object or numeric vector.

- y
`distr6`

object or numeric vector.

- npoints
number of evaluation points.

- idline
logical; if TRUE (default), the line \(y = x\) is plotted

- plot
logical; if TRUE (default), figures are displayed in the plot window; otherwise a
data.table::data.table of points and calculated values is returned.

- ...
graphical parameters.

## Details

If `x`

or `y`

are given as numeric vectors then they are first passed to the
Empirical distribution. The Empirical distribution is a discrete distribution so quantiles
are equivalent to the the Type 1 method in `quantile`

.

## Examples

```
qqplot(Normal$new(mean = 15, sd = sqrt(30)), ChiSquared$new(df = 15))
qqplot(rt(200, df = 5), rt(300, df = 5),
main = "QQ-Plot", xlab = "t-200",
ylab = "t-300"
)
qqplot(Normal$new(mean = 2), rnorm(100, mean = 3))
```