What is the primary use of a scatter plot?

A scatter plot is primarily used to show the relationship between two sets of data. It visualizes how one variable correlates with another, helping to identify trends, correlations, or patterns within the data. By plotting data points on a two-dimensional graph where one variable is represented on the x-axis and another on the y-axis, it becomes easier to see how changes in one variable may affect the other. This visual representation is particularly useful in quality improvement because it can assist in understanding how different factors influence outcomes, pinpointing areas for intervention or further exploration.

In contrast, the other options focus on different types of data representation. The first option deals with the distribution of a single variable, which would be better represented by a histogram or a box plot. The second option discusses illustrating relative frequencies, which is more suited for bar charts or pie charts. The last option, while relevant to data representation, describes trends over time, typically shown using line graphs rather than scatter plots, as scatter plots do not inherently convey temporal progression without additional context.