5. Correlations and Associations

Task B

Author

AJ Smit

1 Task B

Using the Doubs River environmental data, create a plot of pairwise correlations.
Name to two top positive and two top negative statistically-significant correlations.
For each, discuss the mechanism behind the relationships. Why do these relationships exist?
Why do we need to transpose the data? Demonstrate what happens when you do not transpose the data (use the species data).
What are the properties of a transposed species table?
What are the properties of an association matrix? How do these properties differ from that of a i) species dissimilarity matrix and from a ii) correlation matrix?
What is the difference between spp_assoc1 and spp_assoc2? Is the information contained in each markedly different from the other?
Explain the kind of insight we are able to glean from a species association matrix.

2 Assessment Criteria

This Task is not formally assessed.

Reuse

CC BY-NC-SA 4.0

Citation

BibTeX citation:

@online{smit,_a._j.,
  author = {Smit, A. J., and Smit, AJ},
  title = {5. {Correlations} and {Associations}},
  url = {http://tangledbank.netlify.app/BCB743/tasks/Task_B.html},
  langid = {en}
}

For attribution, please cite this work as:

Smit, A. J., Smit A 5. Correlations and Associations. http://tangledbank.netlify.app/BCB743/tasks/Task_B.html.

---
title: "5. Correlations and Associations"
subtitle: "Task B"
author: 
  - "AJ Smit"
---

```{r code-brewing-opts, echo=FALSE}
knitr::opts_chunk$set(
  comment = "R>", 
  warning = FALSE, 
  message = FALSE,
  fig.width = 4.5,
  fig.height = 2.625,
  out.width = "75%",
  fig.asp = NULL, # control via width/height
  dpi = 300
)

ggplot2::theme_set(
  ggplot2::theme_minimal(base_size = 8)
)
ggplot2::theme_set(
  ggplot2::theme_bw(base_size = 8)
)
```

## Task B

1.  Using the Doubs River environmental data, create a plot of pairwise correlations.

2.  Name to two top positive and two top negative *statistically-significant* correlations.

3.  For each, discuss the mechanism behind the relationships. Why do these relationships exist?

4.  Why do we need to transpose the data? Demonstrate what happens when you do not transpose the data (use the species data).

5.  What are the properties of a transposed species table?

6.  What are the properties of an association matrix? How do these properties differ from that of a i) species dissimilarity matrix and from a ii) correlation matrix?

7.  What is the difference between `spp_assoc1` and `spp_assoc2`? Is the information contained in each markedly different from the other?

8.  Explain the kind of insight we are able to glean from a species association matrix.

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## Assessment Criteria

This Task is not formally assessed.