Measures of Central Location

Measures of central location tell us about the typical values observed for variables. The mean tells us the average value, the median tells us the middle, and the mode tell us the most frequent. Adrian describes these in the video.

The three are similar in that they all describe the centre of the data, but remember to bear in mind their differences and when they are appropriate. The mean is easy to interpret, but if you have outliers you might not want to use it. The mode tells you the most common observation, but doesn’t make much sense if you have lots of unique values or no values appear more than once. The median isn’t sensitive to outliers, but if you have an even number of data points then it can result in impossible values.

More than knowing how to calculate different statistics, a good analyst should know when they are appropriate and how to interpret them. Now we have some tools for determining what the middle of our data looks like, it’s time to think about how spread out our data is. The mean might be 5, but how spread out around this value is my data? In the next step, we discuss measures of spread to help answer this type of question.