Frequency: How often something happens. 

Pictogram: is a way of showing data using images.

Bar Chart: is a graphical display of data using bars of different heights.

Pie Chart: A Pie chart is a special chart that uses sectors to show relative sizes of data.  

Line Graph: a graph that shows information connected in some way (usually as it changes over time).

Continuous Data: Quantitative data that has an infinite number of possible values within its range. Continuous data is measured.

Discrete Data: Quantitative or qualitative data that only takes certain values. Discrete data is counted.

Primary Data: Data that has been collected from the original source for a specific purpose. 

Secondary Data: Data that is not originally collected by a group for a specific purpose (e.g. using national statistics)

Box Plot: is a diagram showing five pieces of information of a set of data (lowest value, lower quartile, median, upper quartile and highest value)

Histogram: is a graphical display of data using bars of different heights. 

Class Intervals: The range of each group of data.

Frequency Density: is the frequency per unit for the data in each class.

Cumulative Frequency: It is the 'running total' of frequencies.

Median: The middle piece of data in an ordered set of data.  

Lower Quartile: The first quartile of the way through the data. (25%)

Upper Quartile: The third quartile of the way through the data. (75%)

Interquartile Range: is the difference between the upper quartile (75%) and the lower quartile (25%) in an ordered data set. (Interquartile range = upper quartile - lower quartile)