A tally chart which records data in groups rather than distinct values. May be used when individual values would have no or little data recorded.

# Class

Another way of saying group.

# Group

How a set of data may be linked together.

# Tally Chart

A table used to record frequencies. Uses tally marks to show frequency. Data is grouped into bundles of 5.

# Bar-Line Chart

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

# 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.

# Pictogram

A diagram which represents data using symbols.

# Value

How much something is worth.

# 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.