Bar Chart

A diagram that uses bars to represent frequencies. The longer/taller the bar the higher the frequency. Only used for discrete data, so equal gaps must be between the bars.

Key

An important part of any diagram that uses symbols or unusual ways of representing data. Allows the reader to interpret what they are seeing.

Formula

An algebraic statement with a letter equal to an expression. Used to work out a missing variable by substituting in all other known variables. Plural is formulae.