I like graphs, add them any time you can. It is my opinion that the purpose of a graph is to clarify the data. To create a picture of the quantifiable information that shows people what is happening much more clearly than just viewing the numbers alone. This being said, I have a few simple rules that will allow you to get a high marks on any graphs you generate for me.
- Make them as large as you can and still fit on the page. If the purpose is to clarify the data, then a small graph is not serving that purpose. A general rule of thumb, at least 3/4 of the page devoted to the actual data points is good.
- Label each axis clearly and include the units. For example, simply telling me that the "y" axis is temperature without telling me that it is in Celsius will surely lose points.
- Title your graph with exactly what you are showing us. For example, if you are graphing the temperature of 50 ml of distilled water when a 25 ml ice cube is placed in it for 5 minutes, then your title should reflect these facts. "Temperature Change of 50 ml Water with 25 ml Ice Over a Five Minute Period" Great title, everyone knows what they are looking at.
- Make it neat and clean. Use a ruler, make small precise points. If there are two data points in exactly the same place, put them in the same place! See your graph as a work of graphic art. Be proud to put your name on it. If computer generated, be very sure that you have not obstructed any information and that all you data is visible. Arrange it until it looks good.
Follow these simple rules and you will be a graphing guru.
Basic Types of Graphs and When to Use Them:
- Show when something changes over time (it doesn't have to be time but it usually is). In line graphs using time vs. some other value, time is usually the X axis.
- Comparisions of similar characteristic. For example comparing the densities of different metals
Pie Graphs (This graph needs a good title)
- Showing the parts of a whole amount. Percentages are parts out of 100. Often percentages are used in Pie Graphs but not always, use the units you are given, if you also want to convert it into percentages in addition to the units you were given, then show both values in your graph.
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