stat_qq {ggplot2} | R Documentation

## Calculation for quantile-quantile plot.

### Description

Calculation for quantile-quantile plot.

### Usage

    stat_qq(mapping = NULL, data = NULL, geom = "point",
      position = "identity", ..., distribution = stats::qnorm,
      dparams = list(), na.rm = FALSE, show.legend = NA, inherit.aes = TRUE)

    geom_qq(mapping = NULL, data = NULL, geom = "point",
      position = "identity", ..., distribution = stats::qnorm,
      dparams = list(), na.rm = FALSE, show.legend = NA, inherit.aes = TRUE)

### Arguments

`mapping` | Set of aesthetic mappings created by `aes` or `aes_`. If specified and `inherit.aes = TRUE` (the default), it is combined with the default mapping at the top level of the plot. You must supply `mapping` if there is no plot mapping.
`data` | The data to be displayed in this layer. There are three options: If `NULL`, the default, the data is inherited from the plot data as specified in the call to `ggplot`. A `data.frame`, or other object, will override the plot data. All objects will be fortified to produce a data frame. See `fortify` for which variables will be created. A `function` will be called with a single argument, the plot data. The return value must be a `data.frame.`, and will be used as the layer data.
`geom` | The geometric object to use display the data
`position` | Position adjustment, either as a string, or the result of a call to a position adjustment function.
`...` | other arguments passed on to `layer`. These are often aesthetics, used to set an aesthetic to a fixed value, like `color = "red"` or `size = 3`. They may also be parameters to the paired geom/stat.
`distribution` | Distribution function to use, if x not specified
`dparams` | Additional parameters passed on to `distribution` function.
`na.rm` | If `FALSE` (the default), removes missing values with a warning. If `TRUE` silently removes missing values.
`show.legend` | logical. Should this layer be included in the legends? `NA`, the default, includes if any aesthetics are mapped. `FALSE` never includes, and `TRUE` always includes.
`inherit.aes` | If `FALSE`, overrides the default aesthetics, rather than combining with them. This is most useful for helper functions that define both data and aesthetics and shouldn't inherit behaviour from the default plot specification, e.g. `borders`.

### Aesthetics

`stat_qq` understands the following aesthetics (required aesthetics are in bold):

- `sample`

- `x`

- `y`

### Computed variables

sample

  sample quantiles

theoretical

  theoretical quantiles

### Examples

    df <- data.frame(y = rt(200, df = 5))
    p <- ggplot(df, aes(sample = y))
    p + stat_qq()
    p + geom_point(stat = "qq")

    # Use fitdistr from MASS to estimate distribution params
    params <- as.list(MASS::fitdistr(df$y, "t")$estimate)
    ggplot(df, aes(sample = y)) +
      stat_qq(distribution = qt, dparams = params["df"])

    # Using to explore the distribution of a variable
    ggplot(mtcars) +
      stat_qq(aes(sample = mpg))
    ggplot(mtcars) +
      stat_qq(aes(sample = mpg, colour = factor(cyl)))

[Package ggplot2 version 2.1.0 Index]