qqPlot | R Documentation |

Quantile-Quantile Plots With the Ability to Draw Confidence Bands.

```
qqPlot(y, x = "norm", ...,
type = "p", xlim = NULL, ylim = NULL,
xlab = if(is.numeric(x)) deparse(substitute(x)) else x,
ylab = deparse(substitute(y)),main="Q-Q Plot",
col = 1, lty = 2, lwd = 1, pch = 1, cex = 0.7, plot.it = TRUE,
confidence = .95, qqline = c("observed","expected","none"),
add = FALSE)
```

`y` |
A numeric vector of data values. |

`x` |
Either a numeric vector of data values, or a character string naming a distribution function such as "norm". |

`...` |
Parameters passed to the distribution specified by |

`type` |
1-character string giving the type of plot desired. |

`xlim` |
The x limits. |

`ylim` |
The y limits. |

`xlab` |
A label for the x axis. |

`ylab` |
A label for the y axis. |

`main` |
A main title for the plot. |

`col` |
Color for points and lines. |

`lty` |
Line type. |

`lwd` |
Line width. |

`pch` |
Plotting character for points. |

`cex` |
Factor for expanding the size of plotted symbols. |

`plot.it` |
Whether or not to draw a plot. if plotting, points outside the confidence bands will be indicated by different a color. |

`confidence` |
Confidence level for the confidence band, or |

`qqline` |
Whether or not to draw a reference line. if "observed", the line passes through the first and third observed quartiles; if "expected", the point (x,y) is expected to fall on the line if x and y follow the same distribution; if "none", no reference line is drawn. |

`add` |
Add to an existing plot if true. |

If `x`

is numeric, a two-sample test of the null hypothesis that `x`

and `y`

were drawn from the same continuous distribution is performed. Alternatively, `x`

can be a character string naming a continuous distribution function. In such a case, a one-sample test is carried out of the null that `y`

was draw from distribution `x`

with parameters specified by "...".

`x` |
Quantiles of |

`y` |
Quantiles of |

`lower, upper` |
Lower and upper limits if |

George Marsaglia, Wai Wan Tsang and Jingbo Wang (2003), Evaluating Kolmogorov's distribution. Journal of Statistical Software 8 (18): 1-4.

Vijayan N. Nair (1982). Q-Q plots with confidence bands for comparing several populations.

William J. Conover (1971). Practical Nonparametric Statistics. New York: John Wiley & Sons.

`ks.test`

.

```
## Not run:
par(mfrow=c(1,2))
x<- rnorm(200, mean=0.7,sd=2); y<- rnorm(200, sd=2)
qqPlot(y,x,qqline="exp")
qqPlot(y=y,x="norm",sd=2)
ks.test(x,y)
## End(Not run)
```

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