# Working with charts, graphs and tables

## 6 Technical glossary

This glossary is intended to provide a basic explanation of how a number of common mathematical terms are used. Definitions can be very slippery and confusing, and at worst can replace one difficult term with a large number of other difficult terms. Therefore, where an easy definition is available it is provided here, where this has not been possible an example is used. If you require more detailed or complete definitions, you should refer to one of the very good mathematical dictionaries that are available, or to one or more books listed in Section 7.

**Approximation:** A numerical result given to a required level of accuracy, for example, to the nearest metre.

**Average:** The word ‘average’ is often used instead of the word ‘mean’ but it can have other interpretations so it is best to use the
appropriate correct term; this is usually ‘mean’, but may be ‘median’ or ‘mode’ (see below).

**Chart:** Pictorial representation of data, e.g. piechart, bar chart.

**Data:** Items of numerical information, raw facts or statistics collected together for analysis.

**Decimals:** A way of expressing numbers using place value,

e.g.

**Fractions:** Parts of a whole number, e.g. , , etc.

**Graph:** A drawing which depicts the relationship between data or values.

**Mean:** A typical value of a set of data; which is equal to the sum of the values in the set divided by the number of values in the
set.

**Median:** The middle point of a set of values arranged in ascending or descending order.

**Mode:** The most common value in a set of data.

**Percentage:** A proportion of a hundred parts, e.g. 75 per cent =

**Ratio:** A comparison of one quantity with another.

**Scale:** A series of marks at regular intervals on a line used for measuring, e.g. the divisions on the axis of a graph or the degree
markings on a thermometer.

**Value:** A numerical amount.