Graphical Representation of Qualitative Data

Bar Charts

Bar charts are a graphical display where the length of each bar represents the number of observations in each category.
Guidelines for constructing bar charts:
- Can be constructed horizontally or vertically.
- Categories should maintain their order.
- The axis scale should enable effective comparison.
- Bars should not be too close or too far apart.
- Bar width should be consistent and visually appealing.
- Space between bars should be about half the bar width.
- Gridlines are optional but can be helpful.
- Labels should be provided on each bar and axis.
Example: Survey of 1250 adults regarding public schools.
- Responses:
  - Excellent: 462
  - Pretty good: 288
  - Only fair: 225
  - Poor: 225
  - Not sure: 50

Pie charts display categorical data as slices of a circle.
The size of each slice is proportional to the frequency of the category.
Most meaningful with 10 or fewer categories; less informative with too many categories.
Example: Representing the survey data from the bar chart example using a pie chart.
- Categories represented as proportional slices:
  - Excellent: 37%
  - Pretty good: 23%
  - Only fair: 18%
  - Poor: 18%
  - Not sure: 4%