Photo of 3D printed tactile Violin Plot
3D printed tactile model of the Violin Plot
Sighted version of the tactile Violin Plot
Sighted version of the tactile Violin Plot

Violin Plot Tactile Chart Exploration Instructions

Follow these instructions to explore the tactile model of a Violin Plot.

Step 1: Orienting the Chart

  • Locate the cut corner at the top-right of the board.
    • Position the chart so this corner remains at the top-right.
  • On the back, there are two stickers:
    • A smaller square label near the cut corner contains a QR code. Scanning it with your phone will take you to a companion website.
    • A larger rectangular label provides a labeled version of the chart.

Step 2: Introduction to the Violin Plot

  • This tactile model represents a Violin plot, which visualizes distributions of quantitative data for one or more categories. A distribution describes how values in a dataset are spread out. For example, if you collect the weight of 100 penguins, the distribution will show how many penguins are light, average weight, and heavy, respectively.
  • Move your hand to the top-left corner to feel the title: "Violin Plot."
  • Explore the board to get an overview. The chart is located on the center of the board.
  • The data: In this model, we are exploring the body mass (in pounds) of three penguin species:
    • Adelie
    • Chinstrap
    • Gentoo
  • There are three violin-plot shapes, each showing the body mass distribution for a species of penguins.

Step 3: Exploring the Violin Plot

  • Finding the Origin:
    • Move your hand to the bottom-left corner of the plot. This is where the Y-axis and X-axis intersect.
  • Y-Axis and Scale:
    • Start at the bottom-left corner and trace the Y-axis upward.
    • The Y-axis is a vertical line with tick marks and Braille labels, encoding body mass in pounds.
    • At the top of Y-axis is the y-axis label in Braille: body mass (lb)
    • Feel the evenly spaced tick marks and their Braille labels, which represent body mass measurements:
      • The bottom tick (at the corner) is 5 pounds, which means the Y-axis starts from 5 pounds.
      • The next tick above is 6 pounds, then 7 pounds, 8 pounds, and so on, increasing evenly to the top tick, which is 14 pounds.
      • The even numbers are marked out with Braille numbers.
  • X-Axis and Species Labels:
    • Return your hand to the bottom-left corner and trace the X-axis horizontally.
    • The X-axis is a horizontal line with evenly spaced Braille labels for each species, from left to right: Adelie, Chinstrap, and Gentoo.
    • These labels correspond to the violin plots directly above them.
  • Violin Shapes:
    • Three violin shapes, each positioned above a species label show the distribution of body masses for that species.
    • Locate the first violin from the left. This represents the distribution of body masses for Adelie penguins.
    • Trace the outer contour of the violin with your fingers:
      • The violin is symmetrical left to right.
      • Wider sections of the violin represent more values, meaning that a higher number of penguins have a body mass around this value.
      • Skinnier sections represent fewer values, meaning that few penguins have a body mass around this value
    • Refer to the Y-axis or tactile grid lines to identify the corresponding body mass values.
    • Inside each violin, you will feel a dashed horizontal line, which marks the median body mass for that species.
    • Move your hand to the right and repeat this process for the Chinstrap and Gentoo violins.
    • Touch the three violins to compare the shapes and medians to understand differences in distribution.
      • For the left violin representing Adelie penguins note that:
        • The distribution has one peak, meaning that it is unimodal, and is symmetrical.
        • The widest section is centered at the median (8.16 pounds), where most data points are concentrated, indicating that most Adelie penguins have body masses around this value.
        • The density tapers off symmetrically on both sides, showing a relatively balanced distribution with fewer penguins at the lower and upper extremes.
      • For the middle violin, representing Chinstrap penguins:
        • The distribution also has one peak and is symmetrical. The peak near the median body mass is about 8.18 pounds.
        • The peak is more distinct compared to Adelie penguins. The violin is wider, indicating that Chinstrap penguins' body masses are more tightly clustered around the median. The tails at both ends are skinnier than that of Adelie penguins. This suggests lower variability in body mass compared to Adelie penguins.
      • For the right violin, representing Gentoo penguins:
        • The distribution is bimodal, meaning there are two distinct peaks in body mass. The first peak appears around 10.5 pounds, and the second peak near 12 pounds, forming two areas of high density. This suggests that Gentoo penguins exhibit greater variation in body mass, possibly due to differences in sex with males having distinctly higher body mass than females.
        • The median body mass of 11.02 pounds is higher than that of Adelie and Chinstrap penguins, and about as high as the heaviest penguins of the other species.
        • The median is closer to the lower peak (10.5 pounds) rather than centered between the two peaks, indicating that more Gentoo penguins have body masses around the lower peak than the higher peak. This suggests an asymmetry in distribution, where the higher peak represents fewer but more widely spread heavier penguins.
        • The violin also has a more elongated distribution compared to the other two species, showing Gentoo penguins have a larger body mass range.

Step 4: Recap

  • Y-Axis: Represents body mass in pounds, increasing from 5 to 14 (vertical scale).
  • X-Axis: Identifies penguin species (horizontal labels).
  • Violin Shapes: Show the distribution of body masses, with wider sections indicating higher density and horizontal lines marking the medians.