PRC Data Visualization & Communication 2 — Questions and Answers
Question 1: Which chart type is most appropriate for showing the composition of a whole across multiple categories?
- Line chart
- Stacked bar chart (Correct answer)
- Scatter plot
- Box plot
Correct answer: Stacked bar chart
Stacked bar charts show part-to-whole relationships while also enabling comparison across categories.
Question 2: A researcher wants to communicate uncertainty in survey estimates to a non-technical audience. What is the most accessible approach?
- Report the standard error in a footnote
- Include confidence intervals as shaded regions on a chart (Correct answer)
- List p-values in an appendix
- Use standard deviation in the legend
Correct answer: Include confidence intervals as shaded regions on a chart
Shaded confidence interval regions on a chart visually convey uncertainty in an intuitive, non-technical way.
Question 3: When presenting longitudinal data with multiple overlapping trend lines, which technique best reduces visual clutter?
- Increase line thickness for all series
- Use small multiples (faceting) (Correct answer)
- Add data labels to every point
- Change the y-axis to logarithmic scale
Correct answer: Use small multiples (faceting)
Small multiples separate each series into its own panel, reducing overlap while preserving comparability.
Question 4: What does the preattentive attribute 'color hue' most effectively encode in data visualization?
- Quantitative magnitude
- Categorical group membership (Correct answer)
- Temporal sequence
- Statistical significance
Correct answer: Categorical group membership
Color hue is a preattentive attribute best suited for encoding categorical distinctions, not ordered quantities.
Question 5: A research report must comply with accessibility standards (WCAG). Which visualization practice is most critical?
- Using only grayscale charts
- Ensuring sufficient color contrast and adding text alternatives (Correct answer)
- Limiting charts to two colors
- Avoiding all interactive elements
Correct answer: Ensuring sufficient color contrast and adding text alternatives
WCAG compliance requires adequate contrast ratios and text alternatives (alt text) so visualizations are accessible to users with visual impairments.
Question 6: Which principle does Edward Tufte's 'data-ink ratio' promote?
- Maximizing decorative elements to engage readers
- Eliminating non-data ink to make every mark count (Correct answer)
- Using bright colors to highlight key findings
- Adding gridlines to every chart for precision
Correct answer: Eliminating non-data ink to make every mark count
Tufte's data-ink ratio principle advocates removing all chart elements that do not directly represent data.
Question 7: In a research presentation, a dual-axis chart is being considered. What is the primary risk?
- It cannot display time-series data
- It can create misleading impressions of correlation or scale (Correct answer)
- It requires proprietary software to create
- It is incompatible with color-blind palettes
Correct answer: It can create misleading impressions of correlation or scale
Dual-axis charts often mislead viewers into perceiving false correlations because the two y-axes can be scaled independently.
PRC Data Visualization & Communication 2
Which chart type is most appropriate for showing the composition of a whole across multiple categories?