What is a Pie Chart?
A pie chart is a circular statistical graphic divided into slices to illustrate numerical proportion. Each slice's arc length is proportional to the quantity it represents.
Frequently Asked Questions
How do I format data for a pie chart?
Each line should be formatted as 'Label: Value'. For example: 'Apple: 35'. The tool automatically calculates percentages.
How many categories can I have?
Up to 10 categories for best readability. More than 10 slices can become hard to distinguish.
Key Terms
- Proportion
- The fraction of the total represented by each slice.
- Category
- Each distinct group shown as a colored slice.
- Percentage
- The proportion expressed as a percent of the total.
Computation Method
- Quartiles are calculated using linear interpolation (method 7 from Hyndman & Fan, 1996), consistent with Python's NumPy and pandas defaults.
- Outlier detection uses the Tukey fences method: lower fence = Q1 − 1.5 × IQR, upper fence = Q3 + 1.5 × IQR.
- Chart scaling caps the display axis at the upper fence value so the visualization remains clear even when extreme outliers are present.
References
- Tufte, E. R. (2001). The Visual Display of Quantitative Information. 2nd ed. Graphics Press.
- Cleveland, W. S. & McGill, R. (1984). "Graphical Perception: Theory, Experimentation, and Application to the Development of Graphical Methods." Journal of the American Statistical Association, 79(387), 531–554.