# Glossary

The glossary provides information on the meanings of technical terms. For information on the definitions of individual variables and data items please see the section on Data Definitions and Specifications.

TERMMEANING
Averages There are three types each of which are defined separately, they are the; mean; median; and mode.
Histogram A form of bar chart where the bars represent counts of items within value ranges. They are useful for describing distributions.
Mean A type of average. The mean is often simply called the “average” as it is the one most commonly known. If all the values in a dataset are added together then the mean is obtained by dividing the sum of the values by the total number of individual values.
Median A type of average. If all the values in a data set are ranked in order, the middle value will be the median. When there is an even number of data items, the values of the two middle values are averaged using the mean. At least half of the values will be greater than or equal to the median.
Mode A type of average. The most common value in a set of data. A peak in a distribution will be at the mode.