For more information, please see full course syllabus of AP Psychology

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For more information, please see full course syllabus of AP Psychology

For more information, please see full course syllabus of AP Psychology

### Research Methods: Correlation

- Correlation is a descriptive method to determine relationships between and among variables
- Correlations help us identify relationships that are worth knowing and are valuable for making predictions
- Correlation does NOT demonstrate causation
- A positive correlation indicates the presence of one PREDICTS the presence of the other
- A negative correlation indicates the presence of one PREDICTS the absence of the other
- It is statistically impossible to have a correlation coefficient greater than +1.00 or lesser than –1.00

### Research Methods: Correlation

Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.

- Intro
- Correlation Overview
- Correlations
- Helps Identify Relationships Worth Knowing About
- Helps Make Predictions
- If Correlation Exists Then the Two Variables are Related
- Correlation Does NOT Equal Causation
- A Third or Extraneous Variable Can Create the Appearance of a Correlation Between Two Unrelated Variables
- Correlation Only Indicates the Strength of Relationship Between Two Variables.
- Correlation
- Indicates Positive or Negative Relationship Between Variables.
- Positive Correlation: Presence of One Variable Predicts the Presence of Another
- Negative Correlation: Presence of One Variable Predicts the Absence of Another
- Characteristics of Correlation
- Describes Strength of Relationship
- Measured by Formula; Result Always Between -1 and +1
- Statistically Impossible For Value to be Greater Than +1 or Less Than -1.
- Regardless of Being Positive or Negative The Stronger Correlation Value is the One Furthest From Zero
- Look for Association or Relationship Between Two Variables to Determine Correlation
- Formula
- Spearman Rank Correlation Coefficient
- Sign (+/-) Indicates Nature of Relationship, Number Determines Its Strength
- Causation
- Remember Correlation Does Not Equal Causation
- An Existing Strong Relationship Doesn't Mean One Creates the Other
- Example: The Relationship Between Crime and Unemployment
- Third or Extraneous Variable May Cause the Appearance of a Strong Correlation
- Terms
- Scatterplot and Scattergram Mean the Same Thing
- Drawn Demonstration of What a Scatterplot Looks Like
- Characteristics of Scatterplot Showing Perfect Positive or Negative Correlation
- Terms
- Positive Correlation: Increases in One Measure (X) Matched by Increases in Another (Y)
- Example: Relationship Between Smoking Cigarettes and Contracting Lung Cancer
- Zero correlation: No Relationship Exists Between Two Variables
- Example: Correlation Between Hair Color and IQ Score
- Terms
- Negative (Inverse) Correlation: As Values of One Measure Increase (X), Values of Another (Y) Decrease.
- Example: The More Alcohol You Drink, the Lower Your Score on a Coordination Test Will Be
- Scatterplots for correlations
- Strong Positive Correlation Scatterplot Will Have Points Running Upwards Closely Along a 45 Degree Angle Line
- Strong Negative Correlation Will Have Points Running Downwards Closely Along a 45 Degree Angle Line.
- Examples of Scatterplots Showing Weak Positive Correlation, Zero Correlation, Moderate Negative Correlation and Weak Negative Correlation
- Google Search for Positive Correlation
- Google Search for Negative Correlation
- Google Search for Zero Correlation
- Examples (Use the Thumb Method)
- Review Questions

- Intro 0:00
- Correlation Overview 0:14
- Correlations 0:32
- Helps Identify Relationships Worth Knowing About
- Helps Make Predictions
- If Correlation Exists Then the Two Variables are Related
- Correlation Does NOT Equal Causation
- A Third or Extraneous Variable Can Create the Appearance of a Correlation Between Two Unrelated Variables
- Correlation Only Indicates the Strength of Relationship Between Two Variables.
- Correlation 1:24
- Indicates Positive or Negative Relationship Between Variables.
- Positive Correlation: Presence of One Variable Predicts the Presence of Another
- Negative Correlation: Presence of One Variable Predicts the Absence of Another
- Characteristics of Correlation 2:01
- Describes Strength of Relationship
- Measured by Formula; Result Always Between -1 and +1
- Statistically Impossible For Value to be Greater Than +1 or Less Than -1.
- Regardless of Being Positive or Negative The Stronger Correlation Value is the One Furthest From Zero
- Look for Association or Relationship Between Two Variables to Determine Correlation
- Formula 4:19
- Spearman Rank Correlation Coefficient
- Sign (+/-) Indicates Nature of Relationship, Number Determines Its Strength
- Causation 4:57
- Remember Correlation Does Not Equal Causation
- An Existing Strong Relationship Doesn't Mean One Creates the Other
- Example: The Relationship Between Crime and Unemployment
- Third or Extraneous Variable May Cause the Appearance of a Strong Correlation
- Terms 5:36
- Scatterplot and Scattergram Mean the Same Thing
- Drawn Demonstration of What a Scatterplot Looks Like
- Characteristics of Scatterplot Showing Perfect Positive or Negative Correlation
- Terms 6:44
- Positive Correlation: Increases in One Measure (X) Matched by Increases in Another (Y)
- Example: Relationship Between Smoking Cigarettes and Contracting Lung Cancer
- Zero correlation: No Relationship Exists Between Two Variables
- Example: Correlation Between Hair Color and IQ Score
- Terms 7:23
- Negative (Inverse) Correlation: As Values of One Measure Increase (X), Values of Another (Y) Decrease.
- Example: The More Alcohol You Drink, the Lower Your Score on a Coordination Test Will Be
- Scatterplots for correlations 7:43
- Strong Positive Correlation Scatterplot Will Have Points Running Upwards Closely Along a 45 Degree Angle Line
- Strong Negative Correlation Will Have Points Running Downwards Closely Along a 45 Degree Angle Line.
- Examples of Scatterplots Showing Weak Positive Correlation, Zero Correlation, Moderate Negative Correlation and Weak Negative Correlation
- Google Search for Positive Correlation 8:41
- Examples of images of charts showing different degrees of positive correlation
- Google Search for Negative Correlation 8:53
- Examples of Charts Showing Different Degrees of Negative Correlation
- Google Search for Zero Correlation 9:08
- Examples of Charts Showing Zero Correlation Between Two Variables
- Examples (Use the Thumb Method) 9:22
- Which Examples Demonstrate Positive, Negative, and Zero Correlation?
- Review Questions 11:15
- What Kinds of Correlations Are Likely With The Relationships Below?

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