How to build graphs, charts and plots

For Categorical data• If the data is

nominal, then:• Few values: Pie

Chart• Many Values:

Pareto Chart (order of bars determined by frequency)

• If the data is ordinal, then:• Bar Graph (order

of bars determined by order of the ranking variable)

For Numerical Data• Value classes are

contiguous intervals that cover all possible data values

• Frequency counts can be made one class at a time (non-cumulative), or one more class every row (cumulative).

• Frequency counts can also be absolute or relative

Graphs for numerical dataGraph Horizontal

AxisVertical Axis

HistogramBar Graph

Class Midpoints

Non-cumulative Frequency

F or %Polygon

Line ChartClass

MidpointsNon-cumulative

FrequencyF or %

OgiveLine Chart

Upper Class Limits

Cumulative Frequency

F or %

Other graphs for numerical data• Time Series plot

• Excel’s Insert|Graph Tab• Stem-Leaf plot

• Excel’s data analysis tools

Other graphs for numerical data• Run Chart• Box-Whisker plot (excel add ins)