It's easy to compare trends when they're represented on the same graph.
Another type of graph that shows relationships between different data series is the bar graph.
You must always use the same unit of measure within a pie chart. The pie chart in Figure 8 shows where ABC Enterprise's sales come from. If you want to emphasize one of the segments, you can detach it a bit from the main pie. For all their obvious usefulness, pie charts do have limitations, and can be misleading.
Be careful not to use too many segments in your pie chart. Click here for a thoughtful argument against use of pie charts.
Data can also be represented on a horizontal bar graph as shown in Figure 7.
This is often the preferred method when you need more room to describe the measured variable.
However, the chances are that your point will be lost if you rely on these alone.
Put up a graph or a chart, and suddenly everything you're saying makes sense!Line graphs simply use a line to connect the data points that you plot.They are most useful for showing trends, and for identifying whether two variables relate to (or "correlate with") one another. By plotting sales figures on a line graph, as shown in Figure 3 , it's easy to see the main fluctuations during the course of a year.This is certainly true when you're presenting and explaining data.You can provide tables setting out the figures, and you can talk about numbers, percentages and relationships forever.Graphs or charts help people understand data quickly.