Sometimes Cumulative frequencies are of interest so one might use a cumulative frequency table giving the number of observations less than or equal to a few selected values. A histogram is a chart that represents a frequency table. The heights of the bars equal the frequencies in the bins. A relative frequency histogram represents a relative frequency table with the heights of the bars equal to the relative frequencies in the bins. A pie chart is one way.
Slices are proportional to the number or observations in each category.
The relationship between two quantitative variables can be displayed with a scatter diagram.