RLO: Descriptive statistics for interval and ratio scale data

Median

The median value is not used as often as the mode and mean, yet it provides another perspective on similarity within our data. In our street we get everyone to line up in order of their ages. So we have the youngest standing to the left and the next to them is the next youngest, and so on until we have the eldest to the extreme right. The age of the person in the middle of the row is known as the median. This is easy to find if we have an odd number of people, because the person in the middle is the one who has the same number standing on their left as they do on their right

When there is an even number of people then we have to find the two values in the middle and take a simple average of these two values. Assume that in our row from the street we have twenty people. The middle point is that point between the 10th person from the left and the 11th person. Why? Well, at the point between these two people there are 10 people on the left of the point and 10 people on the right of the point.

The median, like the mean and the mode is often used to identify the similarity between values. If, in our street, we find that the median age is 35 years, and the average is 35 years this also says something about the distribution of ages. Whereas if the median value is separated from the mean, say 28 years, then this indicates a skew in the distribution of scores