An exploratory data analysis is an approach to analysing data that includes examining boxplots, stem-and-leaf plots and histograms, to gain an insight into the data prior to statistical analysis.

A line graph represents data as a series of points connected by a line.  It is most appropriate when you independent variable, on the x-axis, is continuous and quantitative. Line graphs are also appropriate when you want to illustrate functional relationships among variables.

Line graphs can also be used to display the means from a factorial experiment.

If your data are in the form of proportions or percentages, then you might find a pie chart a good way to represent the value of each category. A pie chart represents the data as slices of a circular pie. Although they may look nice, you very rarely see pie charts in results sections of reports or articles and so are best advised to leave them alone, they are moer usually found in newspapers, magazines and some applied research reports.