regression correlation · Lesson 1 of 8
Scatter Plots
Scatter Plot
A scatter plot displays the relationship between two quantitative variables by plotting data as points on an x-y coordinate plane. The explanatory variable goes on the x-axis, the response variable on the y-axis.
What to Look For
Examine the direction (positive, negative, none), form (linear, curved), and strength (how tightly clustered the points are). Also look for outliers and unusual patterns.
Example
Plotting study hours (x) vs exam score (y) for 30 students. If the points trend upward from left to right, there is a positive association: more study hours tend to correspond to higher scores.
Best Practice
Always start with a scatter plot before computing correlation or fitting a regression line. The plot may reveal nonlinearity or outliers that summary statistics alone would miss.