GRAPHICAL REPRESENTATIONS OF STATISTICS ARE WIDELY USED in the field of educational technology. Unfortunately, statistics are often manipulated to represent information supporting a particular point. The following examples show how graphs can be changed to give the observer a different perspective.

Bar graphs can be changed so that the difference between bar heights is minimized. The smaller the increments between each number on the y axis, the more definition there is between the different bars. As the numbers on the y axis increase, the difference between bars is smaller. The bars appear to be closer in height.
Look at the example to the right. The first graph is scaled to 800 and the difference in referrals between the grade levels is quite apparent. As the numbers on the y axis change, so does the height of the bars and the difference between bars is less evident. 

The size of the elements used in a graph can affect the way a person perceives the information. If the object or bar is drawn with greater area, the viewer sees a larger difference between the objects. The graph to the right demonstrates this concept. With the enlarged light bulb, it appears that Vista uses much more electricity than National City. Click on the graph to see a better representation of the data.

Extras are added to graphs to emphasize a piece of information. Pie graphs are often used with an exploded piece. Sometimes this piece is not much greater than another piece, but the emphasis causes the viewer to see it as more. Pie charts are valuable, but research shows that people prefer bar graphs. The graphs to the right show three ways of expressing information.

1. This graph uses an exploded pie piece when it is not that much larger than some of the other pieces.
2. This is a fair representation of the data using a pie chart.
3. Research has shown that bar graphs are easier for viewers to read and comprehend.

Julie Garcia