19 February 2013

Class Exercise 5

Task: Practical exercises for learning when and how to use tables and graphs

Class exercise 5 is based on the book Show Me the Numbers by Stephen Few. There are several scenarios, in which each requires one to make choices to determine the most effective design for communicating a quantitative message. The choices involved the following:
  • Should the message be presented in the form of a table or a graph?
  • If a table, which kind of relationship?
    • Between a single set of quantitative values and a single set of categorical subdivisions
    • Between a single set of quantitative values and the intersection of multiple categories
    • Between a single set of quantitative values and the intersection of hierarchical categories
    • Among a single set of quantitative values associated with multiple categorical subdivisions
    • Among multiple sets of quantitative values associated with the same categorical subdivision
  • If a graph, which kind of relationship does it need to display?
    • Nominal comparison
    • Time-series
    • Ranking
    • Part-to-whole
    • Deviation
    • Frequency distribution
    • Correlation
  • If a graph, which object or combination of objects for encoding the quantitative values would work best?
    • Points
    • Lines
    • Points and lines
    • Bar
The scenario given to me is Scenario #4.
"You have been promoted from Director of customer service to Vice President of Service . Before you were able to move full time into your new position, you had to recruit someone to replace you as director. Your company spreads the work of customer service across four different customer service centers, one in each of four major geographical region. Customers are able to rate their experiences with the service centers by responding to survey distributed via email. Because you want the new director to focus on improving the centers that are scoring lowest in customers' ratings, you need to provide her with the mean rating of service for each service center during the most recent quarter. In what form will you present these summarized ratings?"

For this scenario, there are only 4 numbers involved, namely the mean rating of the most recent quarter for the different regional service centers. It will be better if tables are used instead of graphs since very little information is involved, thus a graph would be redundant. The kind of relationship will be between one set of qualitative values and one set of categorical subdivisions. The outcome can look like the following table. The region can also be arranged in descending order to allow the new director see clearly which customer service center has the highest mean and which customer service center has the lowest mean.

Region
Mean Rating for Q3
South
10
East
8
North
7
West
4

No comments: