## Quantile-Quantile Plots

## Usage

    qqnorm(y, ylim, main = "Normal Q-Q Plot", xlab = "Theoretical Quantiles",
           ylab = "Sample Quantiles", ...)
    qqline(y, ...)
    qqplot(x, y, plot.it = TRUE, xlab = deparse(substitute(x)),
           ylab = deparse(substitute(y)), ...)

## Description

`qqnorm` produces a normal QQ plot of the values in `y`. `qqline` adds a line to a normal quantile-quantile plot which passes through the quartiles.

Graphical parameters may be given as arguments to `qqnorm`, `qqnorm` and `qqline`.

## See Also

`ppoints`.

## Examples

    y <- rt(200, df = 5)
    qqnorm(y); qqline(y, col = 2)
    qqplot(y, rt(300, df = 5))
    data(precip)
    qqnorm(precip, ylab = "Precipitation [in/yr] for 70 US cities")

[Package Contents]