Scatter Diagram
1. The problem is to understand how to create and interpret a scatter diagram, which is a graphical representation of two variables to identify any relationship between them.
2. A scatter diagram plots points on a Cartesian plane where each point represents paired data values $(x, y)$.
3. The formula for each point is simply the coordinate pair: $$ (x_i, y_i) $$ where $x_i$ and $y_i$ are the values of the two variables.
4. Important rules:
- Each point corresponds to one observation.
- Look for patterns such as clusters, trends (positive or negative correlation), or outliers.
5. To create a scatter diagram:
- Collect paired data.
- Plot each pair as a point on the graph.
6. Interpretation:
- If points tend to rise from left to right, there is a positive correlation.
- If points tend to fall from left to right, there is a negative correlation.
- If points are scattered randomly, there is no correlation.
7. Example: Suppose we have data pairs $(1,2), (2,3), (3,5), (4,4), (5,6)$.
- Plot these points on the graph.
- Observe the trend: points generally increase, indicating a positive correlation.
8. Scatter diagrams are useful in statistics and data analysis to visually assess relationships between variables.