Module 2: Data Relationships

Explanatory variable

a variable that may explain or influence changes in a response variable.

Response variable

a variable that measures an outcome of a study.

Strength

A characteristic of a relationship between two variables determined by how close the points in the scatterplot lie to a simple form such as a line.

Direction

indicates whether the overall pattern moves from lower left to upper right, from upper left to lower right, or neither.

Form

approximate functional [blank[. For example, is it roughly a straight line, is it curved, or does it oscillate in some way

Correlation

usually denoted as 𝑟, it measures the direction and strength of the linear relationship between two quantitative variables.

Scatterplot

a plot that displays the relationship between two quantitative variables measured on the same individuals. The values of one variable appear on the horizontal axis, and the values of the other appear on the vertical axis. Each individual in the data appears as the point in the plot fixed by the values of both variables for that individual.

Regression line

A regression line is a straight line that describes how a response variable changes as an explanatory variable changes. We often use a regression line to predict the value of for a given value of when we believe the relationship between and is linear.