A scatterplot shows the relationship between two quantitative variables measured on the same individuals. The explanatory variable goes on the x-axis and the response variable on the y-axis. Drag points, add your own, and practice the four-part description graders look for: direction, form, strength, and unusual features.
Pick a data set, then drag any point. Turn on Click to add points to place new ones. Describe what you see with the four AP words, then check yourself.
The cutoffs here are rough guides, not AP rules. On the exam, any reasonable description earns credit when it matches the graph and is written in context.
The explanatory variable (x) may help explain or predict changes in the response variable (y). Put the explanatory variable on the horizontal axis. Example: hours studied (x) and exam score (y).
Positive: as x increases, y tends to increase. Negative: as x increases, y tends to decrease. A curved pattern that goes down and then up has no single direction.
If the points follow a straight-line pattern, the form is linear. If they bend, the form is nonlinear (curved). A shapeless cloud has no clear form.
Strong means the points hug the pattern tightly. Weak means they are widely scattered around it. Strength is about scatter, not steepness: a steep line can be weak, and a flat-ish line can be strong.
An outlier is a point that falls far from the overall pattern. Clusters are separate groups of points with gaps between them. Always mention them, or say there are none.
A scatterplot shows whether two variables are associated. It cannot show that changing x causes y to change unless the data come from a well-designed experiment.
Each part of the description, what it means, and a model sentence. Always name both variables and the individuals.
| Feature | Options | What to look for | Sample wording |
|---|---|---|---|
| Direction | Positive, negative, none | Do the points rise or fall from left to right? | "As hours studied increase, exam scores tend to increase." |
| Form | Linear, curved (nonlinear) | Would a straight line or a curve summarize the pattern? | "The relationship is roughly linear." |
| Strength | Strong, moderate, weak | How tightly do points cluster around the pattern? | "The points are tightly clustered, so the association is strong." |
| Unusual features | Outliers, clusters, none | Points far from the pattern; separate groups | "The student who studied 3 hours and scored 98 is an outlier." |
| Context | Both variables + individuals | Name what x and y measure and who was measured | "...between hours studied and exam score for these 14 students." |
AP-style multiple choice. Pick an answer to see the explanation.
The vocabulary for topic 5.1. Read the list, flip through flashcards, or quiz yourself. For every term in the unit, see the Unit 5 terminology guide.