What does a line graph primarily illustrate?

A line graph primarily illustrates change over time by plotting data points at intervals along a timeline and connecting them with lines. This visualization effectively shows trends, fluctuations, and patterns in the data, making it particularly useful for observing how a variable evolves over a specific period.

For instance, if you were tracking sales figures across several months, a line graph would allow you to easily see increases or decreases in sales over time, thereby providing insights into performance and helping with forecasting and decision-making. The continuous line helps convey the flow of the data in a clear and easily interpretable manner, which is its primary strength and purpose.

While the other options may relate to data visualization in general, they do not accurately capture the unique role of a line graph. For example, the comparison of parts to a whole is better represented by pie charts or bar charts, while statistical distribution is typically visualized through histograms or box plots. Frequency of occurrences is often depicted using bar graphs or dot plots, but not line graphs. Therefore, the specific focus on time progression solidifies the role of line graphs in data analytics.