What you’ll learn
Interpret quantitative scatter plots.
Key idea
A scatter coordinate stores a measurement on each axis; the dot itself is one paired observation.
One dot is one paired case; quantitative coordinate values are not case counts or causal evidence.
Worked example
Enter the exact value or ordered values in the format requested below.
Quantitative scatter plot, one letter per paired case, x horizontal and y vertical. Name overall direction: positive, negative or none.
Marked coordinates: A=(1, -4); B=(2, -5); C=(3, -9); D=(4, -10).
- The four letters mark four paired observations: (1,-4);(2,-5);(3,-9);(4,-10). Coordinates are quantitative measurements, not counts.
- The overall trend is negative; small deviations from a line do not eliminate its direction. Each dot is one paired case, not x separate cases.
Answer: negative
Quick Check
Relate the graph used in 'Interpret quantitative scatter plots' to an equation, table, transformation, or verbal description.
Paired measurement table (1,4);(2,7);(3,7);(4,10), plotted below. Claim: "Dot B at (2,7) represents 2 different cases with output 7." Connect the table and plot to assess this reading.
Marked coordinates: D=(4, 10); B=(2, 7); C=(3, 7); A=(1, 4).