Mastering Spearman's Rank Correlation in Marine Science: Analyzing Variable Relationships

Practical Skills Day #8. Lesson plan

Spearman’s rank correlation: a mathematical tool used to find out if there is a correlation between two sets of variables, when they are not normally distributed
Null hypothesis (H.): there is no correlation between the two sets of variables
Critical values of r: indicate when the calculated Spearman’s rank is sufficient to suggest a correlation between the two sets of variables
Alternative hypothesis: there is a significant correlation between two sets of variables

Bell ringer#8
Alternative: Describe the characteristics of an ecosystem having a diversity index D close to 1.

How Ocean Acidification Affects Marine Organisms-cont. (15 minutes)
- Students will conduct observations, pH measurement and record shell weight for control and experimental group.
- Students will record all data and observations.
Begin with Bell ringer#8
Lecture/Notes (PPT – slides 42 – 46)
- Students will learn about different types of correlations and their significance. The formula for Spearman’s Rank Correlation is introduced and explained in detail, ensuring students grasp the mathematical foundation of the concept.
- Define correlation and its importance in science. Differentiate between positive, negative, and no correlation.
- Present the formula for Spearman’s Rank Correlation and explain each term.
- Walk through a sample calculation using a simple data set. – slide 43-45
- Discuss how to interpret the resulting value – slide 46
- Below are slides 42-44

Use Student Guided Notes – This year, I’m using Version B Guided Notes with my students, as I’ve noticed they benefit from having more structured support during class.
- It features fill-in-the-blank prompts for key vocabulary and concepts, making notetaking faster and more accessible, especially for English language learners or those with processing difficulties.
Small group activity and Individual practice.
- Students will work in groups (2-3 students) to calculate Spearman’s Rank Correlation using Math Skills 4.3 page 139 – 142 (Coursebook).
- This hands-on activity encourages collaboration and critical thinking.
- Following this, they will individually calculate the correlation for a new data set, reinforcing their understanding and application of the concept. You can find the activity HERE.
- Students will share their results and interpretations with the class, fostering a collaborative learning environment. The discussion will highlight how different factors can affect the correlation and what the results imply about the marine ecosystem being studied.

Exit ticket
- If you opt to have students complete their notes using the Student Guided Notes format during your lecture, then use the bellringer as the exit ticket activity in class.
- If you opt to have students complete their notes using the Student Guided Notes format at home (homework), then use the following exit ticket activity:
  - Exam-style questions – Page 147, Question 6 (Coursebook)