http://www.ck12.org Chapter 7. Organizing and Displaying Data - Basic
This bar graph contains the information that the Board wanted to send to the state but the actual data has been lost.
The ages of the employees have been put into bins that have groups of ages. As a result, you know that 22% of
the employees are between the ages of 20 to 29 but you do not know the age of the employees. It is possible that 3
people are 20, 2 people are 25 and 3 people are 28. There are numerous combinations that could belong in this age
group but that is something that you do not know from this graph. The only information that can be learned from
this graph is the percentage of the employees that fit in each age group.
Bar graphs, whether they display qualitative or quantitative data can be extended to double bar graphs. Graphs of
this nature are used for comparison of data.
Example 3:The new manager of the school cafeteria decided to ask students to choose a favorite food from the
following list:
Hamburgers Pizza Salad Subs TacosOnce the students had made their decisions he created a double bar graph to compare the choices of boys and girls.
The following graph shows the results:
The graph compares the preferences in food of the girls with those of the boys.