Canadian Health Information Management Association Practice Exam

What type of chart is most useful for displaying how a single total quantity is divided among categories?

1. Bar graph.

2. Histogram.

3. Pie chart.

4. Scatter plot.

The correct answer is: Pie chart.

A pie chart is particularly useful for displaying how a single total quantity is divided among various categories because it visually represents the proportions of each category as slices of a circle, where the entire circle represents the total. This format allows viewers to easily compare the relative sizes of each slice, providing an immediate sense of how much of the total each category contributes. In a pie chart, each slice's size corresponds to the fraction of the total that the category represents, making it straightforward to assess which categories are larger or smaller. This visual representation is especially effective for illustrating parts of a whole, as audiences can quickly grasp the contribution of each category to the total. In contrast, other chart types serve different purposes. For example, a bar graph is excellent for comparing quantities across categories but does not inherently represent parts of a whole. A histogram is used for displaying the frequency distribution of numerical data over intervals, and a scatter plot is used to show relationships between two numerical variables, neither of which focuses on the division of a total among categories in the same way that a pie chart does.