Study Notes
Scatter plots are used to display bivariate data and identify relationships between two variables. Correlation describes the relationship's direction and strength, while a line of regression, or line of best fit, helps make predictions based on the data.
- Scatter Plot — a graph that shows the relationship between two sets of data using dots. Example: A scatter plot of temperature vs. ice cream sales.
- Correlation — describes how two data sets are related, indicating if the relationship is positive, negative, or nonexistent. Example: Positive correlation when both variables increase together.
- Line of Best Fit — a straight line drawn through the center of a group of data points on a scatter plot. Example: A line of best fit showing the trend in a scatter plot of study hours vs. test scores.
Exam Tips
Key Definitions to Remember
- Scatter Plot: A graph showing the relationship between two variables using dots.
- Correlation: The relationship between two variables, which can be positive, negative, or none.
- Line of Best Fit: A line that best represents the data on a scatter plot.
Common Confusions
- Confusing correlation with causation.
- Misinterpreting the strength of correlation based on the scatter plot.
Typical Exam Questions
- What is the correlation shown by this scatter plot? Identify if it is positive, negative, or none.
- How do you draw a line of best fit? Ensure it has an equal number of points on either side.
- What predictions can you make using the line of best fit? Use the line to estimate values within the data range.
What Examiners Usually Test
- Ability to draw and interpret scatter plots.
- Understanding of correlation and its types.
- Skill in drawing and using a line of best fit for predictions.