AP Statistics Flashcards: Representing the Relationship Between Two Quantitative Variables
Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026
Review key ideas with interactive flashcards. This set includes 24 cards to help you master important concepts.
What are the four key characteristics that must be included in a description of a scatterplot?
A complete description of a scatterplot must include its form, direction, strength, and any unusual features.
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What are the four key characteristics that must be included in a description of a scatterplot?
A complete description of a scatterplot must include its form, direction, strength, and any unusual features.
What is a bivariate quantitative data set?
A bivariate quantitative data set consists of observations of two different quantitative variables for each individual.
A scatterplot of city population vs. average commute time shows a clear curved pattern where commute time increases sharply after a certain population is reached. What is the form of this association?
The form of this association is non-linear, as the data points follow a distinct curve rather than a straight line.
What are the two main ways to describe the form of a scatterplot?
The form of a scatterplot is typically described as being either linear (following a straight-line pattern) or non-linear (following a curved pattern).
Define negative association.
A negative association means that as the value of one variable increases, the value of the other variable tends to decrease.
What is meant by the 'strength' of an association?
The strength of an association describes how closely the points in a scatterplot follow a particular form or pattern.
Name two examples of unusual features you might find in a scatterplot.
Two common examples of unusual features are clusters (distinct groups of points) and points with large residuals (outliers from the main pattern).
If the points on a scatterplot are very tightly packed around a straight line, how would you describe the strength of the association?
The strength of the association would be described as strong because the points closely follow a clear pattern.
Define positive association.
A positive association means that as the value of one variable increases, the value of the other variable tends to increase as well.
What is meant by the 'direction' of association in a scatterplot?
The direction of association can be positive (as one variable increases, the other tends to increase) or negative (as one variable increases, the other tends to decrease).
In a study examining the effect of daily rainfall on a river's water level, which variable is the response variable?
The river's water level is the response variable because its values are predicted or explained by the amount of daily rainfall.
What is the primary graphical tool used to represent bivariate quantitative data?
A scatterplot is used to represent bivariate quantitative data, showing the relationship between two numeric variables.
What constitutes an 'unusual feature' in a scatterplot?
Unusual features are points or groups of points that deviate from the overall pattern of the data, such as clusters or points with large residuals.
What are clusters in the context of a scatterplot?
Clusters are an unusual feature in a scatterplot where data points are grouped together in distinct, separate areas of the graph.
A scatterplot shows a general positive trend, but the points are very spread out. How would you describe the strength of this association?
The strength of this association would be described as weak because the points do not closely follow the pattern.
Why is it important to describe all four characteristics (form, direction, strength, unusual features) of a scatterplot?
Describing all four characteristics provides a complete and nuanced understanding of the relationship between the two quantitative variables, preventing misinterpretation of the data.
If a scatterplot of hours spent studying versus number of mistakes on an exam shows a downward trend from left to right, what is the direction of the association?
The direction of the association is negative, as more hours spent studying tends to correspond with fewer mistakes.
On which axes are the explanatory and response variables typically placed on a scatterplot?
The explanatory variable is typically placed on the x-axis, and the response variable is placed on the y-axis.
Define scatterplot.
A scatterplot is a graph that shows two numeric values for each observation, with one value plotted on the x-axis and the other on the y-axis.
What does the 'form' of an association describe?
The form of an association describes the overall shape of the points in a scatterplot, which can be categorized as linear or non-linear.
A real estate agent plots the size of houses (in square feet) against their selling price. Which variable is the explanatory variable?
The size of the house is the explanatory variable, as it is used to explain or predict the selling price (the response variable).
What three terms are commonly used to describe the strength of an association?
The strength of an association is typically described as being strong, moderate, or weak.
What is an explanatory variable?
An explanatory variable is the variable used to explain or predict the values of another variable, known as the response variable.
What is a point with a large residual?
A point with a large residual is an unusual feature that lies far away from the overall pattern or form of the other data points in a scatterplot.