Plot Null Hypothesis Significance Tests.
Purpose
nhstplot
is a simple and convenient package to represent graphically the most common Null Hypothesis Significance Tests (NHST).
In other words, it plots the density functions of z, t, F and Chi-squared, adding a cutline at the observed statistic value, scaling it all conveniently, and plotting a label for the p value.
How to use it
First, install the library with install.packages("nhstplot")
, load the library with library(nhstplot)
.
nhstplot
is composed of 4 functions, one for each major NHST test “family” :
- Chi-squared tests (with the
plotchisqtest
function) - F tests (with the
plotftest
function) - t tests (with the
plotttest
function) - z tests (with the
plotztest
function)
They all work quite the same (with minor differences, see the vignette for more info), with very few required arguments:
- The first required argument is the value of the test statistic z, t, F and Chi-squared
- The other required arguments are the degrees of freedom (except for z of course)
See the vignette for examples and options.
Disclaimer
This package is neither for or against NHST. It’s meant to help explain the process, should you want to explain it. A lot of students (and scholars) have no choice but to read articles with (p) values, so they might as well have a better understanding of what it is and what it’s not anyway, right?