How to build graphs, charts and plots

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 data Graph Histogram Bar Graph

Horizontal Axis Class Midpoints

Polygon Line Chart

Class Midpoints

Ogive Line Chart

Upper Class Limits

Vertical Axis Non-cumulative Frequency F or % Non-cumulative Frequency F or % Cumulative Frequency

F or %

Other graphs for numerical data • Time Series plot • Use the scatter plot graph type from Excel’s Chart wizard

• Stem-Leaf plot • PhStat • Descriptive Statistics • Stem-Leaf Plot …

Other graphs for numerical data • Run Chart • Use the scatter plot graph type from Excel’s Chart wizard

• Box-Whisker plot (chapter 3) • PhStat • Descriptive Statistics • Box-Whisker Plot …

Histogram and Polygons in PhStat • To let PhStat graph frequency distributions of the data use the command sequence: →PhStat →Descriptive Statistics →Histogram & Polygons…

Histogram and Polygons in PhStat • Then, you input the proper cell ranges in the dialog box for the procedure: • Variable cell range: range of cells for data. • Bins cell range: class limits for classifying data into tables. • Midpoints cell range to then have PhStat plot histograms and polygon charts of your choosing. • Let’s draw the frequency distribution charts for 2.12 using PhStat in Excel during class …