Most spreadsheet programs have features designed to help you create graphics from your data. These graphics can help you to illustrate the meaning of the numbers on the chart. They can also be used to stimulate interest, since graphs are often easier to read and understand than a bunch of numbers. Graphics can also be used to help make a point. A well - designed graph can do much to illustrate an idea. Graphs are commonly used in business and scientific settings to illuminate the meaning of spreadsheet data.
There will be a few key elements to any graph.
There are a number of major styles you can choose from when creating a graph. The style you choose implies some things to your readers.
Column charts are like bar charts because they compare distinct items or show single items at distinct intervals. However, column charts have the categories arranged along the horizontal axis and the values along the vertical axis, so the bars are vertical on the chart.
A very common use for column charts is to display how values change
over discrete units of time (monthly or yearly change, for example).
Line charts may also be used to show how the value of a variable changes over time. Unlike bar and column charts, line charts imply continuous change rather than a number of discrete points. For this reason, line charts are better at implying a trend. For example, if you are doing an experiment about the number of fish in a certain pond, you might be interested in the number of fish in the pond at a certain time, but you may also be very concerned with the trend of the fish population. Is it increasing or decreasing?
Just because a line chart implies trends does not necessarily mean they are there! Be careful when interpreting such charts that you do not automatically assume intermediate values by the line placement.
A pie chart is used to show proportions of a whole. It is very useful for figures that relate to a larger sum, such as demographic data or budget information. It is easy to get a feel for the relationship between component values when they are placed in a pie chart. Be careful that you do not have too many slices in the pie, or they will become meaningless.
Also, note that a pie chart is usually used as a snapshot of ONE
moment in time. If you want to show relationships as part of a whole
over time, you would use an area chart. If you want to look at a
number of pie charts at once, you might consider a doughnut chart. (look it up in online help or just play around with it!)
Many of the above charts can be created in 3-dimensional forms. The charts work pretty much the same way, but they can be a little more complex to work with. A three dimensional chart can be rotated so that it can be seen from other perspectives. 3-D charts are often used for the added dramatic impact they provide to a presentation.
Graphs can send a very powerful message to people. The use of images makes a much more vivid impact that straight numbers. Graphs also have the capability to strengthen implications about data based on the type of graph, colors used, and other tools. Just because you see a graph does not mean you should believe it. Examine carefully where the data came from, and what it is telling you.
It is possible to make exactly the same data appear to have completely
different meanings. Examine the figures below for an example:
If you look carefully, you will note that the graphs are both showing exactly the same thing, but by careful manipulation of the graph sizes, axis scales, and titles, the two charts appear to have exactly OPPOSITE meanings.