In this video we will discuss how to justify error bars and add them to your graph.
We will talk about justifying whether you include or omit error bars and see how error
bars look like on a graph.
Error bars are considered under the analysis criterion.
Error bars always use the absolute and not the percentage uncertainty in the given value.
You do not have to write a lot about error bars, you just need a brief comment to justify
them.
Let's see how this is done in the example IA.
First, I explain that I will include horizontal error bars to show an uncertainty of plus
minus 0.2 centimeters in H. Then I add that from my process data table it is clear that
uncertainty in the frequency is negligible, so I will not include vertical error bars.
You can see my error bars in the graph above.
There is no clear rule when you should or should not omit error bars, I usually add
them in the graphing program that I am using and omit them if they are not clearly visible.
The key is to justify your decision.
Finally, the two best programs to use for your graphs and error bars are Excel and if
you are using a Mac probably numbers.
In theory you can also draw your graphs by hand, although students rarely do this.
This completes step 6 action 2, now you know how to justify error bars and add them to
your graph.
In the next video we will discuss how to fit a trend line to your data.