Final answer:
When deciding whether a pie chart is appropriate, it is essential to consider if the data are grouped into categories and if the data represent parts of a whole (100%). However, if the categories overlap and the total exceeds 100%, a pie chart is not suitable, and a bar graph should be used.
Step-by-step explanation:
To determine whether to use a pie chart for displaying data, there are a couple of factors to consider. Firstly, are the data grouped into categories? If yes, a pie chart could be an appropriate choice as it shows how an overall group is divided (grouped into categories). Secondly, do the proportions of these categories represent a relative frequency in comparison to the whole? A pie chart is a suitable visualization for displaying data where each slice can represent a part of a total 100%, indicating relative frequency compared to the whole.
However, if the data points add up to more than 100%, this typically indicates that categories may overlap or participants can be counted in multiple categories. In such cases, the fundamental premise of a pie chart being a representation of 100% is not upheld, making it an inappropriate choice. Instead, a bar graph would be a more suitable option since it can handle categories that are not mutually exclusive and can reflect instances where cumulative percentage can exceed 100%. It is also important to consider aspects such as legibility and clarity when choosing colors and texts for your charts, particularly for sections representing smaller percentages or when displaying total numbers in each category.