# Display the distribution of points for a single condition

## Description

This function creates a plot for a single vector of numerical values, arranging them horizontally from minimum to maximum.

## Usage

    Xplot(x, jitter = FALSE, at = NULL, ...)

## Arguments

`x` |  |  |  | A numeric vector.
`jitter` |  |  |  | Logical, vertically jitter the points.
`at` |  |  |  | The points at which tick-marks are to be drawn. Non-finite (infinite, NaN or NA) values are omitted. By default (when NULL) tickmark locations are automatically computed, see the help file for `?axis`.
`...` |  |  |  | Other graphical parameters from `?par`

## Details

This is a special type of (scatter)plot, with points being arranged only on the horizontal axis (it has no vertical axis). Useful when inspecting if points are grouped into naturally occuring clusters, mainly for crisp calibration purposes.

The argument `...` is used to pass various graphical parameters for the various plotting functions used.

The points have a default `cex` (character expansion) value of 1, and a default `pch` value of 1 (empty points), which can be modified accordingly (for example with value 21 of filled points). When `pch = 21`, the color for the margins of the points can be specified via the argument `col`, while the argument `bg` will determine the fill color of the points.

The axis labels have a default `cex.axis` value of 0.8, which affects both the tickmarks labels and the axis labels.

When jittering the points, default values of 0.5 are used for the parameters `factor` and `amount`, on the horizontal axis. More details can be found in the base function `jitter()`.

Although the points are displayed in a single dimension, on the horizontal axis, the R graphical window will still have the default squared shape, with a lot of empty space on the vertical axis. Users are free to create their custom code to determine the size of the graphics window, or simply resize it to a suitable height.

## Examples

    # Lipset's raw data
    data(LR)

    # plot the DEV (level of developent) causal condition
    Xplot(LR$DEV)

    # jitter the points vertically
    Xplot(LR$DEV, jitter = TRUE)

    # make the x axis large enough to accommodate all values
    Xplot(LR$DEV, jitter = TRUE, at = pretty(LR$DEV))

    # clip plotting between the range of min and max
    Xplot(LR$DEV, jitter = TRUE, at = range(LR$DEV))

## Author

Adrian Dusa

## See also

`par`, `text`, `jitter`