Hi there!
The quote was made by Benjamin Disraeli, but Mark Twain was the one who made it popular, especially in the United States. Basically, it means that you can create charts, graphs, and tables to make a point, even if that point is not true. For example, you can change the axes on a graph. If you want two bars in a bar chart to look the same height, you can simply expand the axis. If you want them to look very different, you can start the axis at a non zero value, for example. Therefore, even if they are similar, you can make the look different, and vice versa. In a pie chart, you can comine slices of the pie, if you want to make them look larger. In a line graph, you can change the axes in a similar way to the bar graphs.
Let me know if you have any questions,
Scott
MIT Graduate
College degree in math... proficient in all levels -- from algebra to calculus