Which type of graph is used to show the number of cases over time in an outbreak?

The type of graph commonly used to show the number of cases over time during an outbreak is a line graph. This is because a line graph effectively depicts trends and changes over a continuous time scale, making it easier to visualize how the number of cases rises and falls over a period. The use of points connected by lines allows for a clear representation of the data over time, which is essential for understanding the dynamics of an outbreak.

Point, bar, and pie charts serve different purposes. Point graphs typically represent discrete data and do not convey trends effectively. Bar graphs are useful for comparing quantities across different categories but are not ideal for showing changes over time since they typically represent data at specific intervals rather than continuous data. Pie charts illustrate parts of a whole, making them unsuitable for depicting trends over time. In contrast, the line graph offers a straightforward way to analyze how the number of cases fluctuates, which is crucial during an outbreak investigation.