Maths tutor, examiner, consultant

Drawing graphs – Top 180 pop records example

In GCSE Science and Maths you are often asked to draw or interpret graphs – representing and visualising data are the technical terms. Often it depends on whether the data is discreet or continuous.

Continuous data can be almost anything – a temperature measurement for instance – and line graphs are generaly used – whereas discreet tends to be categories that can only have certain values and bar charts are best. As an example here is an assessement I did for my hobby – assembled the top 3 pop singles each year for the last 60 years. I used a bar chart to show which artists had appeared more than twice. Not suprisingly the Beatles, Elvis and Michael Jackson were at the top. If you are pop rock and soul fan you can see the full list and how they they were chosen in this link.

As part of my tuition I run through each of the types of graphs you can see here including scatter, line, Pie, box plot, bar, cumulative frequency, histogram. These are becoming ever more important to understand with the new GCSE’s coming next year with Maths.

Another favourite with the examiners expecially with science is the concept of independent and dependent variables. Independent variables are the things you change deliberately e.g. the size of the pellets in a chemcial reaction, and these normally go on the x-axis. These “cause” a change in the dependent variables which are the “effect” i.e.they tend to be continuous, could be the reaction rate, and are usually on the y axis of a graph. Finally the “control variable” is something you keep the same to be fair, such as as room temperature or weight of pellets.

There is often a cross over between Maths and Physics so if you learn about Distance Time graphs in Maths you will also see efectively the same graph in Physics.

And often you will be asked to interpret a graph about which you know nothing such as the drunkne rat biology question – the key is not to panic and instead apply the pronciples you have learned about graph interpretaton.