2.5 Correlation

• In a negative correlation, as one variable increases, the other tends to decrease
• What happens to the second variable in a negative correlation as the first variable increases?

  Decreases
• A correlation coefficient (r) near 0 indicates a strong correlation.

  False
• There is a positive correlation between a person's height and their weight
• In a positive correlation, the direction is positive
• A correlation coefficient of -1 indicates a strong negative correlation.

  True
• A linear relationship between two variables is represented by a straight line on a scatterplot.


  True
• Match the relationship type with its characteristic:

  Linear Relationship ↔️ Constant rate of change

  Non-Linear Relationship ↔️ Varying rate of change
• What does a correlation coefficient close to -1 indicate?

  Strong negative correlation
• What is the key difference between causation and correlation?

  Causation implies direct cause
• Smoking directly causes lung cancer, illustrating a causal relationship
• Warmer weather in the summer is a common factor between ice cream sales and drowning incidents.


  True
• Spearman's correlation is highly sensitive to outliers.

  False
• Spearman's correlation uses raw numerical values instead of ranks.

  False
• In a negative correlation, as one variable increases, the other tends to decrease
• Match the type of relationship with its graphical representation:

  Linear Relationship ↔️ Straight line

  Non-Linear Relationship ↔️ Curved or bent line
• A correlation coefficient of 0.3 indicates a strong positive correlation.

  False
• What type of correlation exists between tire wear and distance driven?

  Perfect negative
• Spearman's Rank Correlation uses rank values rather than raw data.
• A weak correlation has a correlation coefficient close to 0.
• In a positive correlation, as one variable increases, the other tends to increase
• What happens to the second variable in a positive correlation as the first variable increases?

  Increases
• A zero correlation indicates no discernible linear relationship between variables
• What happens to the other variable in a positive correlation as one variable increases?

  It tends to increase
• What is an example of a negative correlation?

  Age and running speed
• What is the measure used to determine the strength of a correlation?

  Correlation coefficient
• What does a correlation coefficient of 1 indicate?

  Strong positive correlation
• A linear relationship has a constant slope
• A correlation coefficient close to +1 indicates a strong positive
• The correlation coefficient only captures linear
• What is an example where correlation does not imply causation?

  Ice cream sales and drowning
• What is the definition of correlation?

  Strength and direction of a linear relationship
• What type of relationship does Pearson's correlation measure?

  Linear
• In which fields is Spearman's correlation most useful?

  Social sciences, economics, and healthcare
• Match the correlation type with its description:

  Positive Correlation ↔️ As one variable increases, the other tends to increase

  Negative Correlation ↔️ As one variable increases, the other tends to decrease

  Zero Correlation ↔️ No discernible linear relationship between variables
• A weak correlation has a correlation coefficient close to 0.


  True
• What does a correlation coefficient of -1 indicate?

  Perfect negative correlation
• Order the correlation strengths from weakest to strongest for negative correlations:

  1️⃣ -0.1 to -0.4

  2️⃣ -0.5 to -0.9

  3️⃣ -1
• What does Spearman's Rank Correlation measure?

  Monotonic relationship
• A strong positive correlation has a correlation coefficient close to +1.


  True