Hello, and welcome to this Excel session. In this video, you'll learn what the median, mode and mean are, and how to use them. The median, mode and mean are the central tendencies we use to describe our data. Let's go through an example of what they show us. 

There are nine people living in this household. We've listed their ages and we'd like to work out the average age. The median is the middle value in the population when you sort them in value order. So here the median age is 23. The mode is the value that occurs the most often. Here, the mode is 16. To work out the mean, we add all of the values together and divide them by the number of values there are. For this household, the mean age is 33. So which one of these describes this household most accurately? As you can see, we have a couple of elderly people living in this household, which affects our mean's central tendency. Most of the people are younger than 33 years old, but the two extreme values, or outliers, have increased the average. Because of this, the mean doesn't represent this household very well. Most of the people in this household are older than 20-years old. So although there are two teenagers in the house, the mode doesn't accurately reflect the whole population. The median is the best central tendency to represent this household. 

Once you've worked out which central tendency most accurately represents your population, you can use that information to decide which models you'll use to analyse your data and prove your hypothesis. And that's it for this video. Thanks for watching. And we'll see you in the next session.