Start here with your data! This is your first question.

How do I know?

Inspect your data with str or summary. Are there several variables?
What does the data show? Does the underlying logic of the data suggest dependencies between the variables?

Example: Inspecting the swiss dataset

1 Univariate statistics
- 1.1 At least one categorical variable
  - 1.1.1 Only categorical data: Chi Square Test
  - 1.1.2 Categorical and continuous data
    - 1.1.2.1 One or two factor levels: t-test
    - 1.1.2.2 More than two factor levels
- 1.2 Only continuous variables
  - 1.2.1 No dependencies: Correlations
  - 1.2.2 Clear dependencies
2 Multivariate statistics

Univariate statistics

How do I know?

Check the entry on Data formats to understand the difference between categorical and numeric variables.
Investigate your data using str or summary. integer and numeric data is not categorical, while factorial and character data is.

At least one categorical variable

How do I know?

Investigate your data using str or summary. integer and numeric data is not categorical, while factorial and character data is.

Only categorical data: Chi Square Test

If you have only categorical variables, you should do a Chi Square Test. LINK TO CHI SQUARE TEST R EXAMPLE

Categorical and continuous data

Statistics flowchart - Categorical factor levels.png

How do I know?

R commands: quantile(), str, summary
Investigate your categorical dependent variables using...
ADD MORE

One or two factor levels: t-test

With one or two factor levels, you should do a t-test. A t-test ... ADD. Check the entry on the T-Test to learn more.

Depending on the variances in your data, the type of t-test differs.

ADAPT THE T-TEST ENTRY SO THAT DIFFERENCE BETWEEN STUDENT AND WELCH IS CLEAR

How do I know?

Use an F-Test to check whether the variances of the datasets are equal. LINK LEFT BOX TO F-TEST

More than two factor levels

MISSING - COMPLICATED FIGURE

Analysis of Variance R commands: aov, Anova, ezAnova, var.test(), lm
Relevant figures: boxplot()

Is your dependent variable normally distributed?

R commands: ks.test, shapiro.test, hist

Yes, my dependent variable is normally distributed!
No, my dependent variable is binomial distributed!
No, my dependent variable is Poisson distributed!

Yes, my dependent variable is normally distributed!

Gaussian Anova R commands: aov, lm
Relevant figures: boxplot

No, my dependent variable is not normally distributed!

Is your dependent variable binomial or Poisson

No, my dependent variable is Poisson distributed!

Poisson GLM|Dependent variable is count data R commands: glm,
Relevant figures: plot

No, my dependent variable is binomial distributed!

Binomial GLM|Dependent variable is 0/1 or proportion R commands:
Relevant figures:

      Type III Anova

R commands: Anova(car)
Relevant figures: boxplot

Data_distribution#Non-normal_distributions|Dependent variable not normally distributed]

Poisson GLM|Dependent variable is count data R commands: glm
Relevant figures: plot

Binomial GLM|Dependent variable is 0/1 or proportions] R commands: glm
Relevant figures:

Only continuous variables

How do I know?

ADD INFO - HOW DO I KNOW IF THEY ARE DEPENDENT?

No dependencies: Correlations

If there are no dependencies between your variables, you should do a Correlation. A correlation ... ADD. Check the entry on Correlations to learn more. The type of correlation depends on your data distribution.

ADD INFO ON PEARSON AND SPEARMAN CORRELATIONS; WITH R CODE

Statistics Flowchart - Normal Distribution.png

LINK TO CORRELATION R EXAMPLES (pearson, spearman)? How do I know?

ADD INFO - HOW DO I KNOW IF THE DATA IS NORMALLY DISTRIBUTED?
Check the entry on Normal distributions to learn more.

Clear dependencies

Statistics Flowchart - Dependent - Normal Distribution.png

How do I know?

ADD INFO - HOW DO I KNOW IF THE DATA IS NORMALLY DISTRIBUTED?
Check the entry on Normal distributions to learn more.

Normally distributed dependent variable: Linear Regression

Not normally distributed dependent variable

Statistics Flowchart - Dependent - Distribution type.png

How do I know?

ADD INFO - HOW DO I KNOW THE DISTRIBUTION TYPE?
Check the entry on Non-normal distributions to learn more.
For both types of distribution, your next step is the Generalised Linear Model. However, it is important that you select the proper distribution type in the GLM ADD MORE INFO

Generalised Linear Models

With non-normally distributed data, you arrive at a Generalised Linear Model (GLM). GLMs are... ADD

Depending on the existence of random variables, there is a distinction between Mixed Effect Models and Generalised Linear Models, which are based on regressions.

Statistics Flowchart - GLM random variables.png

How do I know?

HOW DO I KNOW IF I HAVE RANDOM VARIABLES???
R commands: glmer, glmmPQL

Relevant figures:

WHAT IS THIS ABOUT? Dependent variable is count data

[Binomial GLM|Dependent variable is 0/1 or proportions]]

Multivariate statistics

Statistics Flowchart - Clustering, Networks, Ordination.png

How do I know?

In an Ordination, you arrange your data alongside underlying gradients in the variables to see which variables most strongly define the data points. Check the entry on Ordinations (to be added) to learn more.
In a Cluster Analysis, you group your data points according to how similar they are, resulting in a tree structure.
In a Network Analysis, you arrange your data in a network structure to understand their connections and the distance between individual data points.

Cluster Analysis

So you decided for a Cluster Analysis. A Cluster Analysis .. ADD Check the entry on Clustering Methods to learn more.

There is a difference to be made here, dependent on whether you want to classify the data based on prior knowledge (supervised) or not (unsupervised). DIFFERENCE BETWEEN SUPERVISED AND UNSUPERVISED?? DISTINCTION NOT MADE IN THE CLUSTERING ENTRY

Statistics Flowchart - Cluster Analysis.png

WHERE DO WE LINK?

How do I know?

HOW DO I KNOW IF ITS SUPERVISED OR NOT?

Network Analysis

You have decided to do a Network Analysis. In a Network Analysis... ADD Check the entry on Social Network Analysis to learn more.

There is a distinction here between bipartite and tripartite networks, with two or three kinds of nodes, respectively.

Statistics Flowchart - Network Analysis.png

How do I know?

Check your data using the R code ADD CODE

ADD MORE BELOW - OR DO WE LINK SOMEWHERE ELSE? Bipartite If your data has two different kinds of nodes, your network is called a "bipartite" network.

R commands:

is_bipartite(graph)
make_bipartite_graph(types, edges, directed = FALSE)

Tripartite R commands:
Relevant figures:

Ordinations

How do I know?

Check the entry on Data formats to learn more about the different data formats.
Investigate your data using str or summary. Abundance data is marked as FORMATNAME, and continuous data is marked as FORMATNAME.

MAKE THE STUFF BELOW CLEARER