## Week 6 Preparation and Overview: Correlation vs. Causation

Purpose

To assess your ability to:

• Describe what a correlation is and how it is established.
• Explain the meaning of “correlation does not imply causation”.
• Critically evaluate correlational claims.
• Explain the danger of confusing correlation with causation.
• Identify extraneous or confounding variables.

Overview

In this assignment, you will need to construct your own answers based on the video links, the readings from the key points for this week, and CHAPTERS #8 and #9 of Mark Battersby’s Is that a fact? A field guide to statistical and scientific information

Action Items

Part I

1. In your own words, describe what a correlation is and how it is established.
2. In your own words, discuss what “correlation does not imply causation” means.
3. Read AN ILLUSTRATIVE EXAMPLE: DIET AND CANCER (CHAPTER #8) and critically evaluate the correlational claim. Be sure to answer the four basic CRITICAL QUESTIONS applied to correlation (Chapter 8, section titled 'Evaluating Correlational Claims: The Critical Questions):
1. What does the claim of correlation mean? (What two variables, changing events, factors, or things co-vary? Do they exhibit a positive or negative relation?)
2. How good is the evidence? (Are two relevant groups being compared? Is the difference between the groups large enough (i.e., outside the margin of error of both samples) so that it is unlikely that these differences are the result of chance sampling variation? Were the groups being compared appropriately selected?)
3. What other information is relevant? (What is the context? Have other researchers found similar correlations? Of similar strength? Did other researchers use different types of samples and groups?)
4. Are relevant fallacies avoided? (e.g., consider the fallacies of No comparison, Biased Sampling, Small Sample, Unclear Target Population, and of Significance).

Part II

1. Go to the following links to learn about Crows’ Causal Reasoning:

Choose one video to summarize with complete details (on the basis of what we learned in this moduleand discuss in your own words what is in the crow’s behavior that suggests an understanding of causation.

1. Science in Action: Crows' Casual Reasoning (2:15)
2. How Smart is a Crow? (2:13)
3. Casual Understanding of Water Displacement by a Crow (3:17)
4. Go online and find a news (or magazine) article that confuses correlation for causation. Summarize what you found in your own words and explain the misapplication. Be sure to cite the article’s source(s).
5. Complete Action Items in Parts I and II in a Microsoft Word document.