Select and draw graphs

Use a bar chart for categorical counts, a histogram for quantitative class intervals, a line graph for a time sequence, and a pie chart for parts of a specified whole. A frequency polygon joins class-midpoint frequencies. A less-than ogive plots cumulative frequency against upper class boundaries, starting with zero at the first lower boundary. With unequal class widths, histogram area must represent frequency, so use frequency density f/width. Label axes and units.