Welcome
Everything on the site is free, and all of it is just me sharing the knowledge I collected over the years. It really helps if you would subsribe to my YouTube channel, or if you feel very generous you can do a small (or large :D) donation via Patreon.
The site is split into a few sections. At Fundamentals some basic terms connected to statistics are briefly explained. A good understanding of these is needed to understand the rest of the site. This would be the place to start if you are not familiar with terms like sample, population, measurement level and significance. There is also a subsection at Fundamentals on the basics of SPSS. Note that for all analyses I try to add videos showing how to perform the analyses with SPSS, R and Excel.
At 'One variable' a sub entry is available for each possible type of variable. In each entry it is shown how you can perform a full analysis of it.
The same goes for Two variables - unpaired and Two variables - paired. The unpaired analysis is often used to show if there is an association/relation/correlation between two variables, or if one variable might effect the other. The paired version is if you are interested in differences between two variables or if people changed.
At 3+ variables - paired, you'll find out more about analysing multiple variables if for example you had a question where respondents could pick more than one answer, or if you had a set of questions all using the same scale (Likert items).
The latest addition is the Analyze My Survey section. This explains an Excel tool I created that given all your data, it will perform all possible one-variable, two-variable unpaired, and two-variable paired tests.
The fundamentals section is required to understand for all other parts, but after that you can jump to any section you like.
Note 1: that this site is a simplification of things, and for fundamental research it is important you first dig deeper on the various techniques than described here.
Note2: If you are looking for my older site you can follow it's progress here,
Below an overview of the various tests
| Var1 | Var2 | version | Example question(s) | Visualisation | Test | Post-hoc | Effect size |
| nominal | Would the percentages for each category be equal in the population? | bar-chart | Pearson chi-square goodness of fit | pairwise binomial test with Bonferroni adjustment | Cramer's V | ||
| ordinal | Did at least 50% of the respondents thought it was good (or very good)? | dual-axis bar chart | one-sample Wilcoxon signed rank test | n.a. | correlation coefficient | ||
| scale | Is the average age different from ….? | histogram | one-sample t-test | n.a. | Cohen's D | ||
| nominal | nominal | unpaired | Does gender have an influence on favourite sport? Is there an association (relation) between gender and favourite sport? |
Clustered bar-chart | Pearson chi-square test of independence | Adjusted residuals z-test | Cramer's V |
| nominal | nominal | paired | Did the overall distribution of favourite brand before and after seeing a commercial from each brand changed? | Clustered bar-chart | Bhapkar test | pairwise McNemar test with Bonferroni adjustment | |
| nominal | ordinal | unpaired | Does location have an influence on opinion about….? Are there differences between the different locations on the opinion about….? |
Compound bar-chart | Kruskal-Wallis H test | Dunn's test | epsilon square |
| nominal | scale | unpaired | Does location have an influence on the grade? Are there differences between the different locations and the grades? |
split-histogram | one-way ANOVA | pairwise t-test with Bonferroni or Games-Howell adjustment | eta square |
| ordinal | ordinal | unpaired | Is there a relations/association/correlation between the opinion about …. and the opinion about….? | heat-map | Goodman-Kruskal Gamma | n.a. | Goodman-Kruskal Gamma |
| ordinal | ordinal | paired | Did people's opinion change on a brand after seeing a commercial compared to before the commercial? | Compound bar-chart | Wilcoxon signed rank test | n.a. | correlation coefficient |
| ordinal | scale | unpaired | Is there a relations/association/correlation between the opinion about …. and the grade? | split-histogram | Spearman's rho | n.a. | Spearman's rho |
| scale | scale | unpaired | Is there a relations/association/correlation between the grade for …. and the grade for…..? | scatterplot | Pearson correlation | n.a. | Determination coefficient |
| scale | scale | paired | Did people's income change before vs after they followed a course? | scatterplot | paired samples t-test | n.a. | Cohen's D |
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