Frequency diagramsThese are sometimes called bar charts. These are a good way of looking at the spread of data and are very easy to draw. Remember to number your axes evenly just as you would with a normal algebraic graph. Here's an example: The marks obtained by 30 pupils in a maths test are as follows: First tally them: Now draw your frequency diagram: With grouped data, the bottom axis should be numbered continuously as on a normal graph with the bars covering the group they represent! Line graphsLine Graphs are only used for discrete data and are simply a line (instead of a bar) for each data value showing total frequency. Frequency polygonsAgain, these are done in the same way as Frequency Diagrams but you do not draw the bars. Instead you put a little cross where the middle of the bar would have been then join all the crosses together. Here's what a Frequency Polygon would look like for the example used in Frequency Diagrams above: