Topic+1+-+Statistical+Analysis


 * 1.1.1: State that error bars are a graphical representation of the variability of data**

Below is an example of a graph with error bars.

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The reason we use error bars is because of the uncertainty when measuring data. When one measures with a ruler for example, one cant get the exact amount of accuracy, and that is why we use uncertainty. When that uncertainty is put in a graph, we call them error bars. Take the third bar from the left as an example: The person who created this graph had 90 down for that bar, however he/she thought that it could be as high as 100, or low as 80, and that is why he put them there.

Smaller error bars = more accuracy.

Also, error bars can be used to either measure the range of uncertainty or the standard deviation.


 * 1.1.2: Calculate the mean and standard deviation of a set of values**

How to calculate mean: The mean is just the **average** of the numbers. It is easy to calculate: Just **add up** all the numbers, then **divide by how many** numbers there are. Example 1: Take this set of data and find the mean 3, -7, 5, 13, -2 The sum of these numbers is 3-7+5+13-2 = 12 There are 5 numbers. The mean is equal to 12 ÷ 5 = 2.4