`nhstplot`

is a fairly simple package to use. This vignette is intended to explain the basics (plotting using the defaults), before showing how to use the options.

After installing the library with `install.packages("nhstplot")`

you need to load the library:

`library(nhstplot)`

‘nhstplot’ is composed of 4 functions, one for each major NHST test “family” :

- \(\chi^2\) tests (with the
`plotchisqtest`

function) - \(F\) tests (with the
`plotftest`

function) - \(t\) tests (with the
`plotttest`

function) - \(z\) tests (with the
`plotztest`

function)

Let’s see how to use each one without changing the graphical options.

The `plotchisqtest`

function only requires 2 arguments : The first one is the \(\chi^2\) value (parameter : `chisq`

), and the second one is the degrees of freedom (parameter `df`

).

Here’s an example with respectively 8 and 4.

`plotchisqtest(chisq = 8, df = 4)`

Note that the same is achieved with `plotchisqtest(8,4)`

.

The `plotftest`

function only requires 3 arguments : The first one is the \(F\) value (parameter : `f`

), and the second and third ones are respectively the degrees of freedom of the numerator (parameter `dfnum`

) and the denominator (parameter `dfdenom`

).

Here’s an example with respectively 4, 3 and 5.

`plotftest(f = 4, dfnum = 3, dfdenom = 5)`

Note that the same is achieved with `plotftest(4,3,5)`

.

The `plotttest`

function only requires 2 arguments : The first one is the \(t\) value (parameter : `t`

), and the second one is the degrees of freedom of the numerator (argument `df`

).

Here’s an example with respectively 2 and 10.

`plotttest(t = 2, df = 10)`

Note that the same is achieved with `plotttest(2,10)`

.

By default, the `plotttest`

function plots a two-tailed test. However, a one-tailed test can be plotted by adding the argument `tails = "one"`

:

`plotttest(2, 10, tails = "one")`

The left or right tail is automatically selected using the sign of provided \(t\):

`plotttest(-2, 10, tails = "one")`

The `plotztest`

function only requires 1 argument : The \(z\) value (parameter `z`

).

Here’s an example with a \(z\) value of 2.

`plotztest(z = 2)`

Note that the same is achieved with `plozttest(2)`

.

By default, the `plotztest`

function plots a two-tailed test. However, a one-tailed test can be plotted by adding the argument `tails = "one"`

:

`plotztest(2, tails = "one")`

The left or right tail is automatically selected using the sign of provided \(t\):

`plotztest(-2, tails = "one")`

NHST is a process that isn’t straightforward to explain or understand. Before looking at the \(p\) value itself, it starts with stating a null hypothesis. As a consequence, it can be helpful to provide a “step-by-step” explanation of process that may require to plot the density probability function before adding the cutline and p-value.

Hopefully, all the functions in `nhstplot`

can do that very simply by passing the argument `blank = TRUE`

.

`plotztest(-2, blank = TRUE)`