A graph is defined as a pictorial representation of data or numeric values in an organized manner. Using graph enables us to represent large amounts of data in visual form for easy understanding.
The 2 types of questions about the key features of graphs are interpreting given graphs or selecting a graph based on a verbal description.
The common graph types on SAT are bar graphs, dot plots, histograms, line graphs and scatterplots. Scatterplot subject is covered on scatterplots page.
A Bar Graph is a graphical display of data using rectangular bars (columns) of different heights, so that the height of each bar determines its value. The structure of the bar graph: the y axis contains values, and the x axis contains categories or time periods.
A dot plot is a simple type of graph that shows the frequency with which items appears in a data set. It displays data items as dots above values (or categories) on the x axis (each data item is represented with a dot above its value or category).
A histogram is a frequency bar graph where the data is grouped into ranges. The x axis presents the data ranges and the y axis presents the frequency (the number of values that fall into the specific range.
A line graph includes a line that connects individual data points together. Line graphs are used to show changes over periods of time, so that the x axis represents time values (like years).
Continue reading this page for detailed explanations and examples.