Line graphs are probably the most commonly used type of graph in scientific writing. They show continuous variables and may demonstrate trends or movements over time. They range from simple representations of results to complex statistical analysis. However, they are more difficult to understand than bar graphs. When using a line graph, it is important to keep them simple, to distinguish different variables with different symbols and to label each line.
Logarithmic graphs are similar but use a logarithmic scale.
This is usually done to compare data where the rate of change is more important than the quantity of change. These graphs are also complicated and require more care in their construction and more explanation in the text. Another type of graph is the scatter graph, which show a series of unconnected dots between variables. They can be used to show a relationship and sometimes a line is drawn through the dots to show this relationship. Other times they are used to show that there is no relationship between variables.