Fisher’s exact test is used to determine whether a relationship exists between two categorical variables, for example, students’ gender and their study mode (part-time, full-time).  This test is typically used as an alternative to the chi-square test of independence when sample sizes are small and the variables are dichotomous. In this tutorial we will show … Read more

We use the chi-square test of independence to determine whether there is a relationship between two categorical variables.  For example, we could use it to determine whether there is a relationship between students’ gender and their preferred reading format. The chi-square test compares the observed distribution of frequencies for the two variables with the distribution … Read more

In this tutorial, we will show you how to conduct and interpret a paired samples t-test in R, and how to report the results. The paired samples t-test, also known as the dependent samples t-test, compares the mean difference between two measurements of the same continuous variable.  It is sometimes used in the context of … Read more

The independent samples t-test compares the means of a continuous dependent variable (e.g., exam scores) for two independent groups (e.g., males and females) to determine whether there is a significant difference between them. In this tutorial, we will show you how to conduct and interpret an independent samples t-test in R, and how to report the … Read more

Levene’s test is used to determine whether the variance of a numeric variable (e.g., exam scores) is equal across two or more groups (e.g., male students and female students).  That is, it is assesses equality of variances, an assumption of many statistical tests. In this tutorial we will show you how to compute and interpret … Read more

It is an assumption of many statistical tests that our data be normally distributed.  There are two broad approaches to testing normality.  The first is to assess it visually, by reviewing a graph of the data.  The second is to assess it numerically, by conducting a normality test. In this quick tutorial, we will show you … Read more

Histograms allow us to visualize the distribution of quantitative variables like exam scores. In this tutorial we will show you how to create and customize a histogram in R using the the ggplot2 visualization package.  We will be working in RStudio, a program that makes it easier to work with R. Install and Load ggplot2 Since … Read more

Scatter plots give us a helpful way of visualizing the relationship between two numeric variables.  In this tutorial, we will  show you how to create a scatter plot in R using RStudio, a program that makes it easier to work with R. Install ggplot2 The best way to create a scatter plot in RStudio is … Read more

In this tutorial, we will show you one of the easiest methods you can use to import CSV files into R.   We will be working with RStudio, a program that makes it easier for users to work with R, and we will be using the the readr package.    Quick Steps Type install.packages(“tidyverse”) and click … Read more

In this tutorial, we will show you how to generate random numbers in R. Specifically, we will show you how to generate random numbers from both uniform distributions and normal distributions.   Throughout the tutorial we will be using RStudio, a program that makes it easier to work with R.   Generating Random Numbers from Uniform Distributions … Read more

In this tutorial, we will show you one of the easiest ways to import Excel (.xlsx and .xls) files into R using the readxl package.   We will be working with RStudio, a program that makes it easier to work with R.   Quick Steps Type install.packages(“tidyverse”) and click enter on your keyboard to install the … Read more

In this tutorial, we show you a quick and simple way to import SPSS (.sav) data files into R using the haven package. We will be working with RStudio, a program that makes it easier to work with R.   Quick Steps Type install.packages(“tidyverse”) and select enter on your keyboard to install tidyverse packages From … Read more

In this tutorial we will show you how to report a point-biserial correlation from SPSS in APA style.  First, we will provide two templates that you can use to report your point-biserial correlation in APA style.  Then we will show you how to populate these templates using your SPSS output.  Finally, we will show you … Read more

The point-biserial correlation is a special case of a Pearson correlation.  It measures the strength and direction of the relationship between a dichotomous variable (e.g., pass or fail) and a continuous variable (e.g., exam scores).  A dichotomous variable is a variable that has two values only, for example, male or female, pass or fail.  In … Read more

In this tutorial we will show you how to report your Wilcoxon signed-rank test from SPSS in APA style. First, we give you a template that you can use to report your results.  Then, we explain how to populate this template using the SPSS output from your own test.  Finally, we give you an example … Read more