1. Consider the following chart and answer the following questions

• Which kind of chart is?
• How many attributes are represented?
• Is the data-ink ratio good?
• Is it colorblind-safe? Can the color choice be improved and how?
• Is there something deceptive? What?
• Which is, in your opinion, the goal of this kind of visualization?

1. Which kind of chart is it?
   • A dual-line chart, where two different data series (gold and silver prices) are plotted over time.
2. How many attributes are represented?
   • The chart represents three attributes:
     • Time (X-axis) – representing dates.
     • Gold Price (Y-axis, left side) – measured in dollars per ounce.
     • Silver Price (Y-axis, right side) – measured in dollars per ounce.
3. Is the data-ink ratio good?
   • The data-ink ratio is moderate. The chart effectively presents trends without excessive decoration, but the use of two different Y-axes can make interpretation more complex. The colors and text could be optimized for better clarity.
4. Is it colorblind-safe? Can the color choice be improved and how?
   • The gold (orange) and silver (blue) colors may not be fully colorblind-safe, especially for individuals with deuteranopia or protanopia (red-green color blindness).
   • Improvement suggestions:
     • Use different line styles (e.g., dashed vs. solid) to differentiate the two lines.
     • Add markers (e.g., circles for gold, triangles for silver).
     • Use colorblind-friendly palettes, such as dark blue vs. dark red, or high-contrast shades.
5. Is there something deceptive? What?
   • Yes, a few deceptive elements exist:
     • Dual Y-axes: Since gold and silver have different price scales, their trends might appear more correlated than they actually are.
     • Lack of clear context: The graph does not indicate whether these are adjusted for inflation or if external factors influenced the trends.
     • Potential axis manipulation: If the Y-axis scales are not proportional, the visual interpretation of price movement can be misleading.
6. What is the goal of this kind of visualization?
   • The goal is to compare price trends of gold and silver over time, allowing viewers to observe:
     • Correlations or divergences between the two metals.
     • Market trends and volatility.
     • Investment insights for traders and analysts.

2. Consider the following chart and answer the following questions

• Which type of chart is used? Which is the task supported by the chart?
• How many attributes are displayed, and which is their type?
• Comment the two deceptive aspects of the visualization.
• Is the colormap used for the lines effective?

1. Which type of chart is used? Which is the task supported by the chart?
   • The chart is a multi-line chart with a logarithmic scale, comparing the cumulative deaths per million across different countries.
   • The task supported is trend comparison between different countries to analyze the spread and severity of deaths per million after reaching a threshold of 50 confirmed deaths.
2. How many attributes are displayed, and which is their type?
   • Three attributes are displayed:
     1. Cumulative death number per million (Y-axis, quantitative and logarithmic scale).
     2. Days since reaching 50 confirmed deaths (X-axis, quantitative and linear scale).
     3. Country name (Encoded via line color and labels, categorical).
3. Comment on two deceptive aspects of the visualization.
   • Use of a logarithmic scale:
     • While a log scale helps compare growth trends over time, it compresses differences in higher values, making large variations in death counts look less dramatic.
     • Viewers unfamiliar with logarithmic scales may misinterpret the severity of trends.
   • Lack of clarity on country-specific policies and data inconsistencies:
     • The note at the bottom mentions differences in death recording methods between countries, but these are not clearly explained.
     • Some countries might have underreporting or different counting standards (e.g., including/excluding care home deaths), making direct comparisons misleading.
4. Is the colormap used for the lines effective?
   • Partially effective, but it has issues:
     • Some colors are too similar (e.g., UK and UK-new measure are close in hue).
     • Thin lines make it hard to distinguish overlapping trends.
     • Colorblind-unfriendly: Red-green hues (e.g., Germany vs France) may be difficult for colorblind users.
   • Improvement Suggestions:
     • Use dashed or dotted lines to differentiate similar colors.
     • Make lines thicker to improve visibility.
     • Use a colorblind-friendly palette with high contrast (e.g., blue vs. orange vs. purple).

3. Consider the following infographic shown in a tv show.

• How many attributes do you see mapped in the map?