What type of data representation should be used to summarize students' test scores over time?

The line graph is the most suitable choice for summarizing students' test scores over time because it visually represents how the scores change at different points in time. This type of graph allows for the clarity of trends and patterns, making it ideal for showing progress or shifts in test scores. Each data point on the graph corresponds to a specific time and its associated score, and the points are connected by lines, which easily illustrates the overall direction (increasing, decreasing, or stable) of the scores over the specified period.

Other forms of data representation, such as pie charts and bar graphs, are effective for portions of a whole or comparing categorical data but do not convey the continuity and progression of data over time as effectively as a line graph does. A dot plot provides a simple view of individual data points but lacks the ability to illustrate trends clearly. The choice of a line graph is particularly advantageous when the goal is to display trends or changes over continuous intervals.