What is the purpose of a scatter graph in the Large Data Set?

• A. To display distribution of a single variable.
• B. To explore possible relationships or correlations between two variables.
• C. To show time-series trend across months.
• D. To compare categories.

Answer: (B)

A scatter graph is used to investigate how two quantitative variables relate to each other. By placing one variable on the horizontal axis and the other on the vertical axis, each data pair becomes a point on the plot. Looking at the pattern of points reveals whether there is a relationship: a general upward trend shows a positive relationship, a downward trend shows a negative relationship, and a scattered cloud with no clear pattern suggests little or no relationship. The strength of the relationship is seen in how tightly the points cluster around a line or curve—the tighter the cluster, the stronger the relationship. This type of graph is not about how a single variable is distributed (that would be a histogram or similar), nor does it track a value over time (that’s a line graph), nor does it compare categories (that would use a bar chart).