Bar graphs and pie charts can both be used to represent the same set of data. Pie charts will work better for some data sets, but bar graphs will work better for others.

Read MoreSometimes we talk about two-way data in terms of **independent variables** and **dependent variables**. In the case of one-way data, we had one independent variable, called the individuals, and one or more dependent variables, called the variables. In the case of two-way data, we have two independent categories on which the variables are dependent.