One sample t-test: Definition, Formula, and Examples

This tutorial provides the definition of one sample t-test, the formulas of one sample t-test, examples of manual calculation. Definition and examples of One sample t-test One sample t-test is used to determine whether a mean is different from a specific value. You can calculate a mean based on a sample and compare whether the … Read more

Independent t-test in SPSS

This tutorial shows how you can conduct an independent t-test in SPSS. Note that, independent (sample) t-test is also called two sample t-test. It deals with situations where X1 and X2 are from two different groups of people or objects. For instance, in this tutorial, we are going to compare how female students differ from male students in writing scores. … Read more

Johnson Neyman in R (2 detailed examples)

This tutorial explains how you can do Johnson Neyman in R. You can use the package of “interactions” in R do Johnson Neyman in R. The following is the key R syntax. library(interactions) model <- lm(Y ~ X * M, data = data_file_name) johnson_neyman(model = model, pred = X, modx = M) The meaning of … Read more

Categories R

Johnson Neyman in SPSS (4 steps)

This tutorial explains what the Johnson Neyman technique is, when you can use the Johnson Neyman technique, and how you can do Johnson Neyman in SPSS. What is the Johnson Neyman technique? The Johnson Neyman technique is used for interaction effects with continuous variables as independent variables. In nature, it is a technique to help … Read more

Understanding Interaction Effects in Data Analysis

This tutorial introduces the basic idea of interaction effects in data analysis. This tutorial includes what an interaction effect is, examples of an interaction effect, and the statistical methods to do the analysis. What are interaction effects? (The definition) An interaction effect is when the effect of one variable (e.g., X) on another variable (e.g., Y) is … Read more

Interaction between Categorical and Continuous Variables in SPSS

This tutorial is to show how to do a linear regression for the interaction between categorical and continuous variables in SPSS. We are going to use the dataset called hsbdemo, and this dataset has been used in some other tutorials online (See UCLA website and another website). You can download the SPSS sav file here. … Read more

Select Variables and Save as a New File in SPSS

This tutorial shows how you can select variables and save them as a new file in SPSS (i.e., subset data file). The easiest way is to use SPSS syntax to indicate which variables you want to select and where you want to save them as a new file. The following shows the key SPSS syntax. … Read more

Plot Interaction Effects of Categorical Variables in SPSS

This tutorial shows how you can plot interactions of categorical variables in SPSS. That is, the 2 independent variables (IVs) are categorical variables and the dependent variable is numerical. Since the IVs are categorical variables, we are going to use bar charts to plot the interaction effect. For this tutorial, you can download the dataset … Read more

How to download CSV files from GitHub

This short tutorial shows how you can download CSV files from GitHub. Note that, this is different from read csv files from GitHub (for that, please refer to my other tutorial). Step 1: Right Click “Raw” First, you can go to a GitHub page with the CSV file and then right click the “raw” (see … Read more