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A Case for Simple Tables

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Tables are integral parts of Statistical practice ... comparison of the lower end point of one with the upper end point of another CI. ... – PowerPoint PPT presentation

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Title: A Case for Simple Tables


1
A Case for Simple Tables
  • Martin A. Koschat
  • The American Statictician,
  • February 2005

2
Outline
  • Tables are integral parts of Statistical practice
  • Article argues that tables receive less
    importance than is due to them
  • Discusses
  • Simple Tables
  • Graphically Enhanced Tables
  • Dynamic Tables

3
Introduction
  • Statistical Analysis starts with exploration and
    ends with presentation
  • First analysis is done using flexible data
    analysis techniques including tables and graphs
  • Presentations include tables and graphs to
    communicate findings
  • Graphics have received a lot of attention
  • Tables have been acknowledged less
    enthusiastically

4
The Case
  • A table is a simple structure to arrange numbers
    in rows and columns
  • Often a row corresponds to a case and a column
    corresponds to a variable

5
The Case (Contd.)
  • Reasons to use numbers
  • Least intervention from the analyst (no bias)
  • Numerical data can be easily manipulated and
    transformed (e.g.. To make graphs)
  • Often require less explanation than graphs or
    modeled constructs

6
Some Considerations for constructing Tables
  • Tables straight from computer programs

7
Ideas for construction of tables
  • Entries must be easy to compare
  • Important entries and comparisons should be
    prominently displayed
  • Tools
  • Choice of rows and columns
  • Arrangement of rows and columns
  • Presentation of numbers
  • Use of graphical tools to enhance display

8
Choice of Columns and Rows
  • Numerical comparisons are easier made within
    columns
  • E.g. 53897351.12 53897351.12 5389735.112 Row
    presentation
  • Column presentation
  • 53897351.12
  • 53897351.12
  • 5389735.112

9
Arrangement of Rows and Columns
  • Rows one wishes to compare should be close
    together
  • We read (English) from left to right and top to
    bottom, meaning that the top left quadrant is
    most important

10
Presentation of numbers
  • Not possible to include all digits
  • Most people can retain up to seven digits
  • Best to restrict to five or lesser digits
  • Commas should be added every three digits

11
Simple Graphical Tools
  • Lines
  • Judicious and parsimonious use of lines
  • Shading
  • Creates bands that help determine the column
    position of individual entries
  • Elements you want to compare
  • Similar effect can be obtained by using a space
    and different fonts

12
Adding Graphical Information to Tables
  • Adding graphical elements that themselves contain
    information
  • Within each row a circle proportional in area to
    its numerical value, leading to comparison along
    a row
  • Angled Column names

13
More Tables with Graphical Information
  • A rotated histogram
  • Easier than to interpret a histogram without
    numbers

14
More Tables with Graphical Information
  • Comparison of CIs involves comparison of the
    lower end point of one with the upper end point
    of another CI.
  • Different font and spacing

15
Dynamic Tables
  • Providing a environment that permits an analyst
    to create a multitude of simple tables in real
    time
  • On-line Application of Programming
  • Structuring of data
  • User interface that exploits this structure
  • Speed with which data can be accessed and
    manipulate

16
OLAP
  • Data organized in a multi-way layout along
  • dimensions where each dimension consists of
  • hierarchical variables

17
Commercial OLAP tool
  • Powerplay by Cognos

18
Discussion
  • Strengths
  • Talks about an important, not often mentioned
    topic
  • Gives good examples
  • OLAP, a new tool
  • Weaknesses
  • No universal tool
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