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 …