# scatterplot: A two dimensional scatterplot In psyntur: Helper Tools for Teaching Statistical Data Analysis

## Description

This function is a wrapper around the typical `ggplot` command to create two dimensional scatterplots, i.e. using `geom_point`. It provides the option of colouring point by a third variable, one that is usually, though not necessarily categorical. Also, it provides the option of placing the line of best fit on the scatterplot. If points are coloured by a categorical variable, the a different line of best for each value of the categorical variable is provided.

## Usage

 ```1 2 3 4 5 6 7 8 9``` ```scatterplot( x, y, data, by = NULL, best_fit_line = FALSE, xlab = NULL, ylab = NULL ) ```

## Arguments

 `x` A numeric variable in `data`. Its values are plotted on the x axis. `y` A numeric variable in `data`. Its values are plotted on the y axis. `data` A data frame with the `x` and `y` variables. `by` An optional variable, usually categorical (factor or character), by which the points in the scatterplot are byed and coloured. `best_fit_line` A logical variable indicating if the line of best fit should shown or not. `xlab` The label of the x-axis (defaults to the `x` variable name). `ylab` The label of the y-axis (defaults to the `y` variable name).

## Value

A `ggplot2::ggplot` object, which may be modified with further `ggplot2` commands.

## Examples

 ```1 2 3 4 5 6 7``` ```scatterplot(x = attractive, y = trustworthy, data = faithfulfaces) scatterplot(x = attractive, y = trustworthy, data = faithfulfaces, xlab = 'attractiveness', ylab = 'trustworthiness') scatterplot(x = attractive, y = trustworthy, data = faithfulfaces, by = face_sex) scatterplot(x = trustworthy, y = faithful, data = faithfulfaces, by = face_sex, best_fit_line = TRUE) ```

psyntur documentation built on Sept. 15, 2021, 5:07 p.m.