Unit 1

Question 1

In the Healthcare Costs visualization site https://public.tableau.com/app/profile/stephen.few/viz/HealthcareCosts_1/HealthcareCosts., what property does disease have?

Answer 1

Category

Question 2

Suppose that we have data that measures age, not in years, but simply using the labels infant, adolescent, young adult, and adult. What measurement scale is this?

Answer 2

Ordinal - These ages are categorical, but can clearly be ordered from youngest to oldest. Because they do not have an equal interval, they are not interval scaled.

Question 3

In the Healthcare Costs visualization (Link https://public.tableau.com/app/profile/stephen.few/viz/HealthcareCosts_1/HealthcareCosts), on the two line graphs on the lower right, the colors of the lines encode

Answer 3

Different diseases

Question 4

Which of the following mappings would be the most accurate for age when measured in years? Remember that accuracy refers to whether what we perceive from a visual representation matches the type of variable that that representation encodes.

Answer 4

Using a gradient color scheme from black to light gray, where 0 is black and the highest age in the data is the lightest gray. The ages {2, 30, 11, 31, 67, 44, 47, 77, 90, 84} would be displayed as: (from dark to light dots)
- Age is a ratio variable and the gradient color scheme which just varies intensity is also perceived as a ratio: black is 0 and white is the highest value with other intensities falling in between.

Question 5

In the Healthcare Costs visualization(Link https://public.tableau.com/app/profile/stephen.few/viz/HealthcareCosts_1/HealthcareCosts), the percentage of all patients (regardless of age) with a certain disease is encoded by

Answer 5

Bar lengths

Question 6

In the Healthcare Costs visualization(Link https://public.tableau.com/app/profile/stephen.few/viz/HealthcareCosts_1/HealthcareCosts), what measurement scale is age?

Answer 6

Ratio - Because age has a non-arbitrary absolute zero, plus the properties of category, magnitude, and equal interval, it is a ratio scale.

Question 7

In the Healthcare Costs visualization(Link https://public.tableau.com/app/profile/stephen.few/viz/HealthcareCosts_1/HealthcareCosts), what property does age (recorded in years) have?

Answer 7

All = Category, Magnitude, Equal Interval, and Absolute Zero

Question 8

In the Healthcare Costs visualization(Link https://public.tableau.com/app/profile/stephen.few/viz/HealthcareCosts_1/HealthcareCosts), what measurement scale is disease?

Answer 8

Nominal - We can only check the equality of diseases, so disease only has a the category property. We cannot, for instance, say that one disease is greater than another–there is no natural ordering to the disease data.

Question 9

Which of the following are information visualizations according to Card, Macinlay, and Shneiderman’s definition?

Answer 9

“the use of computer-supported, interactive, visual representations of abstract data to amplify cognition” (p. 7).
Card, S. K., Mackinlay, J. D., & Shneiderman, B. (1999). Readings in information visualization: using vision to think. San Francisco, Calif: Morgan Kaufmann Publishers. Example:
http://vallandingham.me/co2_small_multiple/
https://public.tableau.com/app/profile/covid.19.data.resource.hub/vizzes

Question 10

In the Healthcare Costs visualization(Link https://public.tableau.com/app/profile/stephen.few/viz/HealthcareCosts_1/HealthcareCosts), diseases are encoded by

Answer 10

Different colors